User login

The Centre

Argyle House
Clarence Court, 5 Dee Road,
Richmond
United Kingdom
TW9 2JN

Contact LTF

For enquiries please contact Tony Novissimo
Phone: 0208 408 1000
Email: tony@novissimo.co.uk
info@Londontherapyfoundation.com

News

Health News from NHS Choices

Constantly updated health news across a range of subjects.

NHS Choices News

  • Apathy unproven as early warning sign of dementia

    “Elderly who lose interest in pastimes could be at risk of Alzheimer's,” reports The Daily Telegraph, with other papers reporting similar headlines.

    These incorrect headlines are based on the results of a study that looked for a link between symptoms of apathy and structural brain changes (on brain scans) in over 4,000 older adults who did not have dementia.

    The researchers were interested in discovering whether there were a combination of changes in brain volume and reported symptoms of apathy.

    These symptoms were defined as:

    • giving up activities and interests
    • preferring to stay at home rather than going out and doing new things 
    • not feeling full of energy

    People who reported two or more of the symptoms listed above had significantly smaller total brain volume and grey and white matter volumes, compared to their counterparts.

    Our grey matter contains predominantly nerve cell bodies – it is also where memories are stored and where learning takes place in the brain. White matter contains nerve cell fibres and is responsible for communication between different brain regions. People with symptoms of apathy also had more abnormal changes to their white matter.

    As symptoms of apathy and structural brain changes were assessed at the same time, we don’t know if the two are directly related or if there are other factors at play.

    It’s currently unproven whether keeping both the mind and the body active will prevent dementia, but it can help improve a person’s quality of life.

    Read more about how getting active can improve your wellbeing.

     

    Where did the story come from?

    The study was carried out by researchers from the University Medical Centre Utrecht in the Netherlands; the National Institute on Aging and the Laboratory for Epidemiology, Demography and Biometry in the US; and the Icelandic Heart Association, the University of Iceland, Janus Rehabilitation and Lanspitali University Hospital in Iceland. It was funded by a US National Institutes of Health contract, the US National Institute on Aging Intramural Research Programme, Hjartavernd (the Icelandic Heart Association) and Althingi (the Icelandic Parliament).

    The study was published in the peer-reviewed journal Neurology.

    This story was covered by The Independent, the Daily Mail and The Times. The Mail and The Independent’s coverage was poor, with both newspaper’s reporting that losing interest in hobbies and other activities in old age could be an early sign of dementia or Alzheimer’s. This study did not investigate whether symptoms of apathy were linked to Alzheimer’s or other dementias. Instead, it looked for a link between apathy symptoms and structural brain changes at a particular point in time.

    The Times’ coverage was more measured, as it stressed that a direct causal link between apathy, brain size and dementia risk had not been proven by the study.

     

    What kind of research was this?

    This was a cross-sectional study of 4,354 older people without dementia who were participating in the Age, Gene/Environment Susceptibility-Reykjavik Study. It aimed to discover if there was a link between apathy symptoms (lack of interest, enthusiasm or concern) and structural brain changes.

    Cross-sectional studies only analyse people at one particular point in time. This means that we don’t know whether the appearance of apathy symptoms and brain changes happened at the same time or if one happened before the other. We also don’t know if the two things are directly related or if there are other factors associated with both.

     

    What did the research involve?

    The researchers studied 4,354 older people (with an average age of 76) without dementia who were participating in the Age, Gene/Environment Susceptibility-Reykjavik Study, which is an ongoing cohort study into the effects of ageing and genetics.

    Apathy symptoms were assessed through responses to three items relating to apathy on the Geriatric Depression Scale. The three questions relating to apathy were:

    • Have you dropped many of your activities and interests?
    • Do you prefer to stay at home, rather than going out and doing new things?
    • Do you feel full of energy?

    Brain volumes and total white matter lesions (abnormal changes in white matter) were measured from MRI scans [/conditions/MRI-scan/Pages/Introduction.aspx].

    The researchers compared people with two or more apathy symptoms to those with fewer than two symptoms, to see if there were differences in brain volume and white matter lesions.

    They adjusted their analyses for a wide variety of confounding factors including age, education, skull size, physical activity, depressive symptoms and antidepressant use

    What were the basic results?

    Just under half of participants (49%) had two or more symptoms of apathy. People with two or more symptoms were older and more likely to be women. They also had lower education, were less physically active, had poorer Mini-Mental State Examination Scores, walked slower and often had high blood pressure, mild cognitive impairment, brain infarcts and antidepressant use, as well as higher depression scores.

    After adjusting their analyses for confounders, people with two or more apathy symptoms had significantly smaller total brain volume and grey and white matter volumes than those with fewer than two apathy symptoms. People with two or more symptoms had 0.5% less grey matter and 0.5% less white matter. They also had more white matter lesions.

    Differences in grey matter volumes were particularly noticeable in the frontal and temporal lobes. These are two of the main brain regions, with the frontal lobe (at the front of the brain) involved with higher mental processes like thinking, judging and planning, and the temporal lobe at the sides of the brain (near the temples) involved with memory, hearing and language.

    Differences in white matter volumes were particularly noticeable in the parietal lobe and the thalamus, both of which are involved in processing sensory information from the body.

    How did the researchers interpret the results?
    The researchers conclude that: “in this older population without dementia, apathy symptoms are associated with a more diffuse loss of both grey and white matter volumes”.

     

    Conclusion

    This cross-sectional study found that people who reported at least two symptoms of apathy had significantly smaller total brain volume and grey and white matter volumes than people with fewer than two apathy symptoms. The grey matter contains predominantly nerve cell bodies. It is also where memories are stored and where learning takes place in the brain. White matter contains nerve cell fibres and is responsible for communication between different brain regions. People with symptoms of apathy also had more abnormal changes to their white matter lesions.

    As symptoms of apathy and structural brain changes were assessed together, we don’t know if the appearance of apathy symptoms and brain changes happened at the same time, or if one happened before the other. We also don’t know if the two things are directly related or if there are other factors associated with both.

    This study has found that apathy symptoms are linked to brain changes. However, this study did not investigate whether apathy symptoms were associated with the development of Alzheimer’s or other types of dementia.

    Currently, there is no guaranteed method to prevent dementia. However, evidence suggests that to reduce your risk some forms of dementia you should:

    • eat a healthy diet
    • maintain a healthy weight
    • exercise regularly
    • do not drink too much alcohol
    • stop smoking (if you smoke)
    • make sure you keep your blood pressure at a healthy level

    Keeping your mind active may also help. Read more about possible methods to reduce your dementia risk.

    Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

    Links To The Headlines

    Elderly who lose interest in pastimes could be at risk of Alzheimer's Disease. The Daily Telegraph, April 17, 2014

    Apathy in old age 'an early sign of dementia': Study shows that losing interest in hobbies could mean Alzheimer's. Daily Mail, April 17 2014

    Brain size shrinks in the elderly as apathy grows. The Times, April 17 2014

    Links To Science

    Grool AM, Geerlings  MJ, Sigurdsson S, et al. Structural MRI correlates of apathy symptoms in older persons without dementia. Neurology. Published online April 16 2014



  • NICE highlights how hand washing can save lives

    “Doctors and nurses should do more to stop hospital patients developing infections, an NHS watchdog says,” BBC News reports.

    The National Institute for Health and Care Excellence (NICE) has highlighted how basic hygiene protocols, such as hand washing, may be overlooked by some health professionals, which may threaten patient safety.

    NICE points out that one in 16 people being treated on the NHS picks up a hospital acquired infection such as meticillin-resistant staphylococcus (MRSA).

     “It is unacceptable that infection rates are still so high within the NHS” said Professor Gillian Leng, director of Health and Social Care at NICE. “Infections are a costly and avoidable burden. They hinder a patient's recovery, can make underlying conditions worse, and reduce quality of life.”

    The measures to reduce infection are laid out by NICE in a “Quality Standard” on “Infection prevention and control” and are outlined below.

     

    What has NICE said?

    This NICE Quality Standard lays out six specific statements for NHS staff on preventing and controlling infections. They are based on previous more detailed guidance and are listed below:

    • People should be offered antibiotics according to local guidance about which ones are most suitable. They should only be prescribed antibiotics when they are needed and not for self limiting, mild infections such as colds and coughs, earache and sore throats. This measure is aimed at reducing the problem of antibiotic resistance, which is when an infection no longer responds to treatment with one or more types of antibiotic and so is more likely to spread and can become serious.
    • NHS organisations should aim to continually improve their approach to preventing infection (for example, by sharing information with other organisations and monitoring rates of infection).
    • All health care staff should always clean their hands thoroughly, both immediately before and immediately after coming into contact with a patient or carrying out care, and even after wearing gloves. Hands can usually be cleaned with either soap and water or an alcohol-based handrub; but soap and water must be used when the hands are obviously soiled or contaminated with bodily fluids, or when caring for people with diarrhoea or vomiting. All care providers should be trained in effective hand cleaning techniques. Hand hygiene in hospitals has improved in recent years says NICE, but good practice is still not universal.
    • Staff involved in the care of patients with urinary catheters should minimise the risk of infection by carrying out procedures to make sure that the catheter is inserted, looked after and removed correctly and safely. These procedures include cleaning hands, using a lubricant when inserting the catheter, emptying the drainage bag when necessary, and removing the catheter as soon as it is no longer needed. (A urinary catheter is a thin flexible tube used to drain urine from the bladder).
    • Staff involved in the care of patients who need a vascular access device should minimise their risk of infection by making sure that the device is inserted, looked after and removed correctly and safely. These procedures include using sterile procedures when inserting the device, using the correct antiseptics and dressings, and removing the device as soon as it is no longer needed. A vascular access device is a tube that is inserted into a main vein or artery and used to administer fluids and medication, monitor blood pressure and collect blood samples.
    • Health care staff should give people who have a urinary catheter, a vascular access device or an enteral feeding tube, and any family members or carers who help them, information and advice about how to look after the equipment, including advice about how to prevent infection. Enteral feeding is a type of feeding used for people who cannot eat normally or safely (for example they may have trouble swallowing) in which liquid food is given through a tube directly into the stomach or upper parts of the digestive system.

     

    What are the dangers of not washing hands?

    Bugs (microbes) such as bacteria and viruses can easily be spread by touch. They may be picked up from contaminated surfaces, objects or people, then passed on to others. 

    Effective hand decontamination – either by washing with soap and water or with an alcohol-based handrub – is recognised as crucial in the reducing avoidable infection.

     

    What hygiene procedures should visitors to hospitals follow?

    When visiting someone in hospital, always clean your hands using soap and water or alcohol handrubs. Do this when you enter or leave a patient’s room or other areas of the hospital. Effective hand decontamination relies on an effective technique, which includes:

    • wetting hands with warm water
    • applying an adequate amount of (preferably liquid) soap
    • rubbing this thoroughly onto all hand surfaces (for at least 10 to 15 seconds)
    • rinsing thoroughly
    • drying thoroughly, preferably with disposable paper towel
    • taps should be then turned off with the paper towel to avoid recontaminating the hands

    Alcohol handrub can only be used if hands are free from soling. The handrub needs to be thoroughly rubbed into all hand surfaces until hands are completely dry.

    If you are concerned about the hand hygiene of doctors, nurses or anyone else who comes into contact with the patient you are visiting, you are encouraged to ask them whether they have cleaned their hands.

    Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

    Links To Science

    Hospital infection rates must come down, says watchdog. BBC News, April 17 2014

    One in 16 pick up a bug in FILTHY hospitals: NICE blames staff hygiene and dirty equipment for thousands of deaths. Mail Online, April 17 2014

    Don't forget to wash your hands, nurses told. The Daily Telegraph, April 17 2014

    One in 16 patients in NHS hospitals picks up infection, warns watchdog. The Guardian, April 17 2014

    Wash your hands to cut infections, nurses told. The Times, April 17 2014

    1 in 16 NHS patients pick up infections. ITV News, April 17 2014

    Medics told by watchdog to wash hands often to stop spread of infection. Daily Express, April 17 2014



  • PET scans may improve brain injury diagnosis

    “PET scans could predict extent of recovery from brain injury, trials show,” The Guardian reports. Evidence suggests that the advanced scanning devices may be able to detect faint signs of consciousness in people with severe brain injuries.

    The paper reports on a study that examined how accurate two specialised brain imaging techniques were at diagnosing the conscious state and chances of recovery in 126 people with severe brain damage.

    The people were scanned using Positron Emission Tomography (PET) scans, which use a radioactive tracer to highlight cell activity, and functional Magnetic Resonance Imaging (fMRI) scans, which show blood flow in the brain, to demonstrate areas of activity. The results of these scans were compared for accuracy, with assessments made using an established coma recovery scale.

    The study aimed to see if the scans could accurately distinguish between a minimally conscious state (MCS) – in which there is a chance of recovery – from other disorders of consciousness.

    PET scans correctly identified 93% of people with MCS and accurately predicted that 74% would make a recovery within the next year. The fMRI scans were slightly less accurate, correctly identifying only 45% with MCS and accurately predicted recovery for just 56% of them.

    The brain scans also showed that a third of the 36 people who had been diagnosed as unresponsive by the coma scale actually had brain activity consistent with minimal consciousness, and just over two thirds of these people subsequently recovered consciousness.

    This small study suggests that PET scanning, together with existing clinical tests, could help accurately identify people with the potential to recover consciousness.

     

    Where did the story come from?

    The study was carried out by researchers from the University and University Hospital of Liege (Belgium), University of Western Ontario (Canada) and the University of Copenhagen (Denmark). It was funded by the National Funds for Scientific Research (FNRS) in Belgium, Fonds Léon Fredericq, the European Commission, the James McDonnell Foundation, the Mind Science Foundation, the French Speaking Community Concerted Research Action, the University of Copenhagen and the University of Liège.

    The study was published in the peer-reviewed medical journal The Lancet.

    It was covered fairly in The Guardian and The Times, which understandably looked at the ethical implications for decisions around switching off life support or giving pain relief.

     

    What kind of research was this?

    This diagnostic study looked at how accurate two specialised brain imaging techniques – Positron Emission Tomography (PET) and functional Magnetic Resonance Imaging (fMRI) – were at correctly distinguishing between different conscious states and predicting recovery in people with severe brain damage. This included both traumatic brain damage, which is typically caused by a severe head injury, and non-traumatic brain damage, which can have many causes, such as a stroke or heart attack.

    The brain imaging results were compared with an established coma recovery scale, which is used in the assessment of people with brain damage.

    PET scanning involves injecting a radioactive tracer (fluorodeoxyglucose – which is why the scans are often referred to as FDG-PET), which then produces colourful 3D images that show up cell activity in the body. It is most commonly used in the diagnosis of cancer. fMRI scanning shows up blood flow in the brain, which demonstrates areas of brain activity.

    The researchers point out that in people with severe brain damage and a disordered level of consciousness, judging the level of awareness is difficult. In particular, the researchers aimed to see whether the scans could accurately distinguish between “unresponsive wakefulness syndrome” and a “minimally conscious state”.

    People with “unresponsive wakefulness syndrome” (previously referred to as a vegetative state) differ from people in a coma in that they have their eyes open and show a normal sleep/wake cycle, but aside from this they show no behavioural signs of awareness. Meanwhile, people in a minimally conscious state (MCS) show fluctuating awareness and response to some stimuli (such as instructions or questions). 

    The distinction between them has important therapeutic and ethical implications. As the researchers say, people in MCS are more likely to suffer pain and might therefore benefit from pain-relief and other interventions to improve their quality of life. They are also more likely to recover higher levels of consciousness that those with unresponsive wakefulness syndrome. In several countries, doctors have a legal right to withdraw artificial life support from people with unresponsive wakefulness syndrome, but not those with MCS.

    The researchers also say that up to 40% of such patients are misdiagnosed by traditional clinical examinations. Brain imaging methods are now being developed to complement these bedside assessments, which can assess spontaneous brain activity or specific responses to mental tasks.

    Such methods may help distinguish between people in an MCS and those with unresponsive wakefulness syndrome.

     

    What did the research involve?

    The researchers included 126 people with severe brain damage that were diagnosed at the University Hospital of Liège, in Belgium, between January 2008 and June 2012. They included people with both traumatic and non-traumatic causes for their brain damage. The results were:

    • 41 had been diagnosed with unresponsive wakefulness syndrome
    • 81 had been diagnosed as being in a minimally conscious state (MCS)
    • 4 patients had been diagnosed with locked-in syndrome, (a state where the person is fully conscious but behaviourally unresponsive). These people acted as a control group

    The researchers carried out repeated clinical assessment of the patients using a behavioural test called the Coma Recovery Scale-Revised (CRS-R). This is thought to be the most validated and sensitive method for diagnosing disorders of consciousness. The scale has 23 items and is used by specialist staff to assess hearing, vision, motor function, verbal function, communication and level of arousal.

    The researchers then carried out imaging using PET and fMRI scans, though not all patients were assessed with each technique (if the person moved too much to obtain a reliable scan, the procedure was left out).

    • For the PET, the person was injected with the imaging agent fluorodeoxyglucose before undergoing a scan. The scan from each person was contrasted against 39 healthy adult controls 
    • For the fMRI scan, patients were asked to do various motor and visuospatial tasks during the imaging session – including imagining playing tennis or walking into a house. The patterns of activity in the brain were also compared to those obtained in 16 healthy volunteers

    12 months after the initial assessment, the researchers assessed the patients using a validated recovery scale (the Glasgow Outcome Scale – Extended). This assesses their level of recovery and disability and places the person into one of 8 categories ranging from 1 (death) to 8 (having made a good recovery). They also obtained an assessment of each patient’s outcome from medical reports.

    The researchers then calculated the diagnostic accuracy of both imaging techniques, using the CRS-R diagnoses as the reference “gold standard”.

     

    What were the basic results?

    The main results:

    • PET scanning accurately identified 93% of people in a minimally conscious state (95% confidence interval (CI) 85-98) and had a high level of agreement with behavioural CRS-R scores
    • fMRI was less accurate at diagnosing a minimally conscious state (MCS), correctly identifying 45% of patients (95% CI 30-61) and had lower overall agreement with behavioural CRS-R scores than PET imaging
    • PET correctly predicted outcome after 12 months in 74% of patients (95% CI 64-81), and fMRI in 56% of patients (95% CI 43-67)
    • 13 of 42 (32%) of patients who had been diagnosed as unresponsive with CRS-R showed brain activity compatible with minimal consciousness on at least one of the brain scans; 69% of these (9 of 13) people subsequently recovered consciousness
    • The tests correctly identified all patients with locked-in syndrome as conscious

     

    How did the researchers interpret the results?

    They say the results show that, used together with the Coma Recovery Scale, PET scanning might be a useful diagnostic tool in disorders of consciousness. They also say it would be helpful in predicting which people with MCS might make a long-term recovery.

     

    Conclusion

    This is a valuable diagnostic study that tested how accurate PET and fMRI imaging are at distinguishing between different levels of conscious state and helping to predict recovery. 

    Diagnostic assessments are traditionally made using bedside clinical tests – but as the researchers say, judging the level of awareness in people with severe brain damage can be difficult.

    In particular, the researchers wanted to see whether the scans could accurately distinguish between people with “unresponsive wakefulness syndrome” and “minimally conscious state”, as distinguishing between these two states can have important therapeutic and ethical implications. The study found that PET scanning in particular had a high accuracy for diagnosing MCS and for predicting recovery time.

    It’s particularly noteworthy that PET scans detected brain activity in some people who had been diagnosed as unresponsive by the standard Coma Recovery Scale test, and two-thirds of these people subsequently recovered consciousness.

    However, the study has some limitations, including its small size, some missing data and possible differences between people who were and were not lost to follow-up. As the researchers acknowledge, their study used a complex method of statistical analysis, so there is a risk of false results.

    At a practical level, these specialist types of imaging techniques are expensive and complicated to set up, so could have resource implications.

    Overall, the findings suggest that PET scanning  could be a promising addition to standard clinical assessments, when trying to diagnose people with severe brain damage and disordered consciousness.

    Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

    Links To The Headlines

    PET scans could predict extent of recovery from brain injury, trials shows. The Guardian, April 16 2014

    Brain scanner can detect signs of hope in vegetative-state patients. The Times, April 16 2014

    Links To Science

    Stender J, Gosseries O, Bruno M, et al. Diagnostic precision of PET imaging and functional MRI in disorders of consciousness: a clinical validation study. The Lancet. Published online April 16 2014



  • Cannabis linked to brain differences in the young

    “Using cannabis just once a week harms young brains,” the Daily Mail reports.

    The newspaper reports on an US study that took one-off brain MRI scans of a group of 20 young adult recreational cannabis users, and a comparison group of 20 non-users. They compared their brain structure, focusing on regions that are believed to be involved in addiction.

    They found differences between users and non-users in shape and volume of the nucleus accumbens and amygdala; areas of the brain involved in reward and pleasure responses, emotions, memory, learning, and decision making.

    However, a case could be made that the media has overstated the implications of the research.

    As the study only involved a single one-off brain scan it cannot prove cause and effect. It could be the case that pre-existing abnormalities in the brain make people more likely to use cannabis rather than vice versa.

    The study was small, involving just 20 users and 20 non-users. Examining different groups of people and different age groups could give different results.

    And finally, there is currently no proof that the changes detected to the brain will correspond to any demonstrable differences in thought processes and decision making behaviour.

    That said, due to the widespread use of cannabis, results such as these warrant further study. This may possibly become easier to carry out due to the quasi-legal status of cannabis in some US states.  

    Where did the story come from?

    The study was carried out by researchers from Massachusetts General Hospital, Harvard Medical School, Boston, and Northwestern University Feinberg School of Medicine, Chicago.

    Funding was provided by the National Institute on Drug Abuse, the Office of National Drug Control Policy, Counterdrug Technology Assessment Center, the National Institute of Neurological Disorders and Stroke, and the National Institutes of Health. Individual researchers also received support from Warren Wright Adolescent Center at Northwestern Memorial Hospital and Northwestern University; and a Harvard Medical School Norman E. Zinberg Fellowship in Addiction Psychiatry Research.

    The study was published in The Journal of Neuroscience, a peer-reviewed medical journal.

    By and large the media has made the (potentially incorrect) assumption that cannabis use has harmed the brain and is responsible for alleged changes in behaviour. For example, the Daily Mail headline that “cannabis once a week harms young brains” in particular is not justified by this research.

    The study did not investigate whether the brain changes observed were harmful (for example in terms of thinking or behaviour), they just commented that the brain structures were different. Also, users in the study averaged 11 cannabis joints per week, rather than one.

    This small cross sectional study taking one-off brain scans cannot prove whether cannabis was behind any changes seen to the brain. Observational studies that followed people over time would be able to provide better evidence of this.

     

    What kind of research was this?

    This cross sectional study took MRI scans of the brains of young adults who used marijuana (cannabis) recreationally, and compared them with brain images of adults who did not use cannabis. They were interested in comparing the structure in particular areas of the brain.

    Cannabis is one of the most commonly used illicit drugs, particularly by adolescents and young adults. It has been shown to have effects upon thought processes such as learning, memory, attention and decision-making.

    Previous animal studies have shown that exposing rats to 9-tetrahydrocannabinol (THC), the main psychoactive chemical of cannabis, leads to changes in the structures including the nucleus accumbens. In people the nucleus accumbens is believed to play a central role in the brain’s reward centre and pleasure-seeking behaviour. However, less is known about the relationship between cannabis use and brain structure in people, and this is what this study aimed to look at.

     

    What did the research involve?

    The study included 20 young adults (aged 18–25 years; 9 male) current cannabis users and 20 controls who did not use cannabis. The controls were matched by age, sex, ethnicity, hand dominance and educational level. Cannabis users used cannabis at least once a week but were not considered to be dependent (as assessed using valid diagnostic criteria). They did not include people who met criteria for abuse of alcohol or any other substance. 

    The participants received MRI imaging on one visit to the study centre. They were asked not to use cannabis on that day. They performed a urine screen for any substance. The main breakdown product of THC can be detected in the urine several weeks after last use, so they couldn’t tell from the urine test how long ago participants had last used. But researchers checked that none showed signs of acute intoxication according to criteria on examination (for example fast heart rate, red eyes, slurred speech).

    All participants were scanned using special MRI techniques, specifically looking at the volume, shape and density of gray matter (nerve cell bodies) in the nucleus accumbens and other brain regions that may be involved in addiction.

     

    What were the basic results?

    The researchers found that the gray matter of cannabis users was denser in the left nucleus accumbens, and in other brain regions including the amygdala, a region believed to play an important role in our emotional responses, including fear and pleasure. Correlating with the increased density of nerve cells, the volume of the left nucleus accumbens was also larger in cannabis users than non-users. 

    The higher the reported use of cannabis, the higher the volume of the left nucleus accumbens tended to be, and the greater the density of gray matter.

    Cannabis users and non-users also demonstrated differences in brain shape, particularly in the left nucleus accumbens and right amygdala.

    The observed differences were seen even after adjusting for age, sex, alcohol and cigarette use.

     

    How did the researchers interpret the results?

    The researchers conclude that their study suggests that cannabis use in young recreational users is associated with exposure-dependent alterations in the structure of the core brain regions involved in the reward system.

     

    Conclusion

    This study found differences between young recreational cannabis users and non-users in the volume and structure of the nucleus accumbens and amygdala, which have a role in the brain’s reward system, pleasure response, emotion and decision making.

    However, as this was only a cross sectional study taking one-off brain scans of cannabis users and non-users, it cannot prove that cannabis use was the cause of any of the differences seen. It is not known whether cannabis use could have caused these changes in regular users.  

    Or conversely whether the cannabis users in this study had this brain structure to start with, and that this may have made them more likely to become regular users of cannabis.

    Also, this is a small study comparing the brain structure of only 20 users and 20 non-users. With such a small sample of people, it is possible that any differences in brain structure could have been due to chance. These changes may not have been evident had a larger number of people been examined.

    Examination of different samples of people, and in different age groups, may have given different results.

    Similarly, examining the extent of brain structural change was related to factors such as age at first use, and frequency or duration of use, are less reliable when based on such a small sample of people.

    Confirmation of these tentative findings through study of other groups of cannabis users is now needed. 

    It would also be of value to see whether the structural differences observed actually correlated with any demonstrable differences in thought processes and decision making behaviour.

    As some US states have now, to all intents and purposes, legalised the sale of cannabis, such studies should be easier to carry out.

    It is important to stress that cannabis has uncertain effects on thought processes, emotions and mental health, both in the short and longer term. It is also a class B drug which is illegal to possess or distribute. 

    Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

    Links To The Headlines

    Using cannabis just once a week harms young brains: Study shows emotions and motivation affected. Daily Mail, April 16 2014

    Even casual use of cannabis alters brain, warn scientists. The Daily Telegraph, April 16 2014

    Smoking cannabis could change the part of the brain dealing with motivation, according to one new study. The Independent, April 16 2014

    Links To Science

    Gilman JM, Kuster JK, Lee S, et al. Cannabis Use is Quantitatively Associated with Nucleus Accumbens and Amygdala Abnormalities in Young Adult Recreational Users (PDF, 533kb). Published online April 16 2014

     



  • Eating chocolate probably won't save your marriage

    “As blood glucose levels plummet, aggression levels rise, and people take it out on those closest to them,” The Daily Telegraph reports.

    This news is based on an American study into blood glucoses levels and aggression.

    Researchers aimed to find out whether people’s blood glucose levels predicted aggressive impulses and aggressive behaviour in married couples.

    The thinking behind the study is that as people’s energy levels fall, so does their self-control, making them more likely to lash out (either verbally or physically) to those closest to them. The study included 107 couples, who had their blood sugar measured over 21 days. The researchers measured aggressive impulses by allowing participants to stick pins in a voodoo doll each evening. They were told that the angrier they felt towards their partner, the more pins they should stick in (up to a total of 51!).

    Aggressive behaviour was assessed by measuring the intensity and duration of an unpleasant sound (such as fingernails scratching across a blackboard) that one partner selected for the other as a punishment for losing a competition at the end of the study.

    The researchers did find an association between blood glucose levels and increased results in the tests used to assess aggressive impulses and aggressive behaviour.

    However, this was a highly experimental and abstract study, and it is difficult to assess what, if any, implications it has in a real world setting. It is certainly not the case, as the Daily Express claims, that “chocolate can save your marriage”.

    If you are concerned that your relationship has become abusive – either verbally, physically, or both – call the free 24-hour National Domestic Violence Helpline on 0808 2000 247.

    Where did the story come from?

    The study was carried out by researchers from The Ohio State University, University of Kentucky and University of North Carolina. It was funded by a US National Science Foundation Grant and published in the peer-reviewed journal PNAS.

    Despite headlines to the contrary, the study did not show that “chocolate can save your marriage”. It also didn’t show that married couples who diet are more likely to argue, or that “low levels of blood sugar can increase the risk of a niggling irritation with your partner turning into a blazing row”.

    All that it found was that the lower blood glucose levels were, the more pins participants stuck into the voodoo doll, and the greater the intensity and duration of noise participants set for their spouse as a forfeit for losing a competition.

    There are also a number of limitations to the study, which should be considered. The researchers didn't determine whether the participants were hungry or whether they were dieting at any stage of the study. They also failed to investigate whether having a sugary snack before completing either the voodoo doll or trial tasks changed the outcome. They also didn’t examine whether the participants had impaired glucose tolerance (a marker of diabetes).

    Despite the light-hearted coverage, it is important to state that domestic violence is a serious issue that can affect both men and women. Read more advice for people in abusive relationships.

     

    What kind of research was this?

    This was an experimental study that aimed to determine whether evening blood sugar (glucose) levels predict aggressive impulses and aggressive behaviour in married couples.

    The researchers measured aggressive impulses by allowing participants to stick pins in a voodoo doll, and aggressive behaviour by measuring the intensity and duration of an unpleasant sound that participants selected as the forfeit for their spouse losing a competition.

    The researchers wanted to test how low blood glucose levels may relate to violent tendencies among intimate partners. It is unclear how the results of this highly experimental scenario can be applied to actual relationships where domestic violence occurs.

     

    What did the research involve?

    The researchers recruited 107 married couples to take part in the study. The average age of participants was 36, with an average marriage of 12 years in length, and were given $50 each to take part in the study. The researchers do not say whether any of the couples had any previous experience of intimate partner violence.

    For 21 days, participants measured their blood glucose levels in the morning before breakfast and in the evening before bedtime. Each evening, participants were told to stick between 0 and 51 pins into a voodoo doll that represented their husband or wife, depending on how angry they were with them. Participants were told to do this alone, without their spouse present, and to record the number of pins inserted. The researchers say this was a measure of “aggressive impulses”.

    At the end of the trial, each couple competed against their husband or wife on a task involving 25 trials at the laboratory. The winner of each trial could blast the loser with a loud noise (a mixture of unpleasant noises, such as fingernails on a chalkboard, dentist drills and ambulance sirens) through headphones. The winner could also choose the intensity (between 60 decibels – similar to the noise level of laughter –and 105 decibels – the level of a fire alarm) and the duration (between half a second and five seconds). They could also choose not to blast their spouse with noise.

    The researchers measured the intensity and duration of noise participants set for their spouse. However, unbeknown to them, participants actually competed against a computer. Participants lost 13 of the 25 trials (in a randomly determined order) and heard noise on each of those 13 trials. The computer chose random noise intensity and duration levels for the spouse across the 25 trials. The researchers state that this was a measure of “aggressive behaviour”.

    The researchers aimed to see if there was a link between glucose levels and “aggressive impulses” (the number of pins participants stuck in the voodoo doll), and whether there was a link between glucose levels and “aggressive behaviour” (the intensity and duration of noise participants set for their spouse).

     

    What were the basic results?

    The researchers found that the lower the level the blood glucose level, the more pins participants stuck into the voodoo doll.

    Lower-than-average evening glucose levels were linked to longer and more intense noise used to blast their spouse with after winning trials.

    People who stuck more pins into the voodoo doll across the 21 days also selected louder and longer noise blasts for their spouse.

     

    How did the researchers interpret the results?

    The researchers said: “Our study found that low glucose levels predicted higher aggressive impulses in the form of stabbing pins in a voodoo doll that represented a spouse. This study also found that low glucose levels predicted future aggressive behaviour [sic] in the form of giving louder unpleasant noise blasts for longer durations to a spouse.”

    “There also was a link between aggressive impulses and aggressive behaviour. Lower levels of glucose predicted aggressive impulses, which, in turn, predicted aggressive behaviour. These findings remained significant even after controlling for relationship satisfaction and participant sex. Thus, low glucose levels might be one factor that contributes to intimate partner violence.”

     

    Conclusion

    This study of married couples found that the lower blood glucose levels were in the evening, the more pins participants stuck into a voodoo doll of their husband or wife. Lower blood glucose was also associated with selecting longer and more intense noise to blast their spouse with after winning trials.

    The real-life implications of these findings are unclear. The researchers wanted to test how low blood sugar levels relate to increased violent tendencies towards a partner. It is already known that very low blood glucose can cause symptoms including altered and irrational behaviour (which may include aggression), but this is usually seen in people with diabetes whose blood sugar drops very low, usually below three or four millimoles per litre (known as hypoglycaemia). The actual blood sugar levels of participants in this study were not reported, and as none were reported to have diabetes or impaired glucose tolerance, it is highly unlikely that glucose levels in any of the participants had fallen to a level where you would expect to see such symptoms.

    Most importantly, this study used highly experimental scenarios, where married couples (with no reported experience of partner violence) were asked to carry out two abstract tests. Therefore, the results cannot be applied to real life situations involving domestic violence. 

    Intimate partner violence may have varied complex psychological causes, and it cannot be answered by one general simple cause, such as low blood sugar.

    If you find it difficult to keep aggressive emotions in check and frequently lash out at those around you, you may require anger management training. Read more advice about controlling your anger.

    Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

    Links To The Headlines

    Married couples who diet more likely to argue, study finds. The Daily Telegraph, April 14 2014

    Spoiling for a row? Then check your sugar level. The Independent, April 15 2014

    How chocolate can save your marriage. Daily Express, April 15 2014

    Links To Science

    Bushman BJ, DeWall CN, Pond RS, et al. Low glucose relates to greater aggression in married couples. PNAS. Published online April 14 2014