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Summer 2012, Volume 15 No 4

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Research update


By Mark de la Hey


Babies’ responses to eye contact may provide early sign of autism

The way a baby responds to a person’s gaze may provide an early indicator of their risk for developing autism, according to new research from the University of London in the United Kingdom. The study involved a total of 104 infants, 54 of whom had a familial risk for autism, and a control group of 50 who had no family history of autism. When the infants were between the ages of six and 10 months, researchers used electroencephalography (eeg) to measure electrical activity in their brains as they were shown pictures of peoples’ faces on a computer screen: some were gazing toward the infant, while others were looking away. Seventeen of the infants in the at-risk group went on to develop autism by their third birthday. Those infants in the at-risk group who did not develop autism showed significant differences in their eeg responses to faces that were either looking toward them or away from them, and this was also true of infants in the control group. In contrast, the infants who later developed autism showed no difference in their responses to the two different types of faces. These findings indicate that, in the future, it may be possible to identify infants at highest risk of developing autism, allowing such infants to be targeted for early intervention.

Current Biology, February 21, 2012, v. 22: 338–342. Mayada Elsabbagh et al., Centre for Brain and Cognitive Development, University of London, London, United Kingdom.


Sleep disturbances among most distressing symptoms of cannabis withdrawal

Nightmares, angry outbursts and irritability are among the most intense symptoms experienced by individuals undergoing withdrawal from cannabis, according to research from the University of New South Wales in Sydney, Australia. Approximately 10 per cent of cannabis users develop a dependence, with the likelihood of dependence rising to about 50 per cent among daily users. The available treatments have low rates of success. The study looked at 49 cannabis users who were asked to abstain from using cannabis for two weeks. Ten participants relapsed during the abstinence phase of the study, while urinalysis indicated that another two participants who claimed to have maintained abstinence had actually relapsed. The most intense withdrawal symptoms experienced by participants were nightmares or strange dreams, angry outbursts, irritability and insomnia. Difficulty getting to sleep was the symptom that distressed participants the most, even though it was only the fifth most intense symptom. Highly dependent participants had more intense withdrawal symptoms and experienced more distress related to their symptoms than those who had lower levels of dependence. Overall, the researchers rated the intensity scores as mild to moderate, with highly dependent participants averaging only 28 per cent of the maximum possible score. The severity of cannabis withdrawal was predicted by the severity of dependence, but not by dependence diagnoses, the amount of cannabis consumed, age or gender.

Drug and Alcohol Dependence, December 2011, v. 119: 123–129. David J. Allsop et al., National Cannabis Prevention and Information Centre, University of New South Wales, Sydney, Australia.


Occasional use of hard drugs in middle age increases risk of death

People who continue to use hard drugs on an occasional basis in middle age have an increased risk of death, according to research from the Birmingham VA Medical Center in Birmingham, Alabama. Recent studies indicate that an increasing number of middle-aged adults use drugs occasionally, although their usage generally does not meet the criteria for diagnosis of a drug use disorder. Researchers looked at data on 4,301 adults in four American cities (Birmingham, Chicago, Minneapolis and Oakland) who were involved in a long-term cardiovascular disease study between the years 1987 and 2006. Based on self-report, 7.9 per cent of study participants occasionally used hard drugs (cocaine, amphetamines or opioids) when they were younger but discontinued in middle age (Early Occasional Users), 3.7 per cent reported occasional use that continued or increased in middle age (Persistent Occasional Users), and 2.6 per cent reported heavy use as young adults that continued on an occasional basis in middle age (Early Frequent/Later Occasional Users). The remainder were nonusers. Compared with nonusers, the three groups of users were less likely to have finished high school or college, less likely to be married, more likely to have experienced economic difficulty, and tended to have more adverse upbringings. They were also more likely to be smokers and to engage in risky drinking behaviours. By 2008, 4.6 per cent of participants had died. Early Frequent/Later Occasional Users were five times as likely as nonusers to have died. Persistent Occasional Users were more than three times as likely and Early Occasional Users a little over twice as likely to die, although these latter results were not considered statistically significant. These findings may help clinicians in advising middle-aged patients who continue to dabble in hard drugs.

Journal of General Internal Medicine, January 25, 2012 online, doi: 10.1007/s11606-011-1975-3. Stefan G. Kertesz et al., Center for Surgical Medical and Acute Care Research, Birmingham VA Medical Center, Birmingham, Alabama


People with mental illness more likely to be victims of violence

Adults with mental illness have a significantly higher risk of being victims of violence than the general population, finds a study from Liverpool John Moores University in the United Kingdom. Researchers reviewed 26 scientific studies providing data on a total of 21,557 individuals with disabilities. Seventeen of these studies focused on people with mental illness, comprising a total of almost 5,000 participants. Overall, the studies showed that the prevalence of violence within the previous twelve months was a little over three per cent for people with disabilities in general, but that figure rose to more than 24 per cent for individuals with mental illness. Among people with mental illness, the rate of physical violence was 21.4 per cent, while the rate of sexual violence was 5.5 per cent. Three of the studies provided data indicating that rates of intimate partner violence among persons with mental illness are almost 38 per cent. People with mental illness were almost four times more likely than those without a disability to be the victims of violence, while disabled adults in general were 1.5 times more likely to be the victims of recent violence. The authors note that their data cover only recent violence, and that lifetime rates of exposure to violence are likely to be much higher. They also indicate that the studies they reviewed come from six high-income countries (Australia, Canada, New Zealand, Taiwan, the United Kingdom and the United States) and one middle-income country (South Africa), pointing to a need for comparable research on disability and violence in low- and middle-income countries.

The Lancet, February 28, 2012 online, doi: 10.1016/S0140-6736(11)61851-5. Karen Hughes et al., Centre for Public Health, Liverpool John Moores University, Liverpool, United Kingdom.


Sex-deprived fruit flies driven to drink

Researchers with the University of California, San Francisco, have found that when male fruit flies are deprived of sex, they show a markedly increased preference for alcohol. The researchers introduced one group of male fruit flies to females that had already mated and therefore spurned the advances of the males. A second group was paired with virgin females that were more receptive to their advances. The male fruit flies were then given the opportunity to consume either their usual food or food containing 15 per cent alcohol. Rejected males consumed significantly more of the alcohol-laced food than their sexually satisfied counterparts. When rejected males were subsequently given the opportunity to mate, this reversed the effect of rejection, and they consumed less alcohol than rejected males who were not given such an opportunity. The researchers found that mating increased—while sexual deprivation decreased—levels of a neurotransmitter known as neuropeptide F (npf) in the flies’ brains. Researchers then demonstrated that when they artificially increased npf levels in male fruit flies, this resulted in a decrease in alcohol consumption comparable to that seen among mated flies, while a reduction in npf levels led to an increase in alcohol consumption. They therefore concluded that changes in npf level were the causal link between sexual experience and alcohol consumption. A similar neurotransmitter, neuropeptide Y, is present in humans, raising the possibility that manipulation of neuropeptide Y in humans could one day offer an effective therapy for addictive behaviour.

Science, March 16, 2012, v. 335: 1351–1355. Galit Shohat-Ophir et al., Department of Anatomy, University of California, San Francisco, California.


Smoking to cope with chronic pain may be counterproductive

People who smoke cigarettes as a means of coping with chronic pain may find that their smoking actually exacerbates their pain and reduces their ability to cope with it, according to a new study from Portland VA Medical Center in Portland, Oregon. The study involved 151 chronic pain patients: 79 were smokers, while 72 were non-smokers. Thirty-nine of the smokers reported smoking to cope with their pain, while the other 40 denied doing so. Participants were asked to complete a number of questionnaires examining such things as mood, anxiety and pain-related functioning (the extent to which pain interfered with their life activities). Those who smoked cigarettes to cope with chronic pain reported more intense pain, poorer pain-related functioning, and more fear of pain. There was no difference between nonsmokers and smokers who did not use smoking to cope with their pain on any of these measures. Both groups of smokers had comparable levels of smoking frequency and nicotine dependence, so the differences between them were not likely due to the frequency of withdrawal symptoms. The authors note that it is possible that those smokers who reported using cigarettes to cope with pain may have been more preoccupied with pain, and this preoccupation may be the reason they reported poorer pain-related functioning. They recommend further research to clarify the causal relationships between smoking, coping strategies and pain-related functioning.

The Journal of Pain, March 2012, v. 13: 285–292. Alexander L. Patterson et al., Mental Health and Clinical Neurosciences Division, Portland VA Medical Center, Portland, Oregon.