Research update

CrossCurrents

Alcohol dependency more common in risk-taking men

Risk-taking behaviour and male sex may increase the risk of alcohol dependency for people who have a family history of dependency, according to researchers at the University of Oklahoma. Researchers studied 175 men and women between18 and 30 years old, without alcohol dependency, half of whom had a family history of dependency. All participated in a test of working memory and a test to evaluate whether they were safe or risky gamblers. Scores on both tests have previously been associated with alcohol dependency risk. The two groups did not differ in their level of monthly drinking, but those with a family history of alcohol dependency showed less behavioural control, had lower educational achievement, poorer regulation of their moods and riskier patterns of substance abuse. Nearly half of participants with a family history of alcohol dependency exhibited less behavioural inhibition and antisocial tendencies, according to scores on a sociability test, which evaluated acting spontaneously without thought of the consequences or the feeling of others. In contrast, about 20 percent of those without a family history of alcohol dependency scored low in sociability. Study participants with a family history and behavioural disinhibition also seemed to have deficits in their working memory. Men with a family history and behavioural disinhibition appeared to base their gambling decisions primarily on potential monetary rewards, while those without a family history took potential losses into account, as well, and consequently made more balanced decisions. The authors caution that although individuals with all of these risk factors may have a higher risk of developing alcohol dependency, not all of them will develop dependency.

Alcoholism: Clinical and Experimental Research, May 2006 online, doi:10.1111/j.1530-0277.2006.00089.x. William R. Lovallo et al., Veterans Affairs Medical Center, University of Oklahoma.

 

Mental health issues may not affect longevity in HIV

HIV-positive individuals with mental health disorders survive as long as HIV-positive people with good mental health, according to researchers at the Victorian HIV Psychiatry Consortium in Melbourne, Australia. Researchers performed a retrospective analysis of all 2,981 individuals who received care for HIV between1984 and 2000. They cross-referenced this population with the Victorian Psychiatric Case Register (VPCR) database of mental health clients and found that 525 individuals matched. Substance abuse was the most common psychiatric disorder (17%), followed by affective disorders (9%) and personality disorders (2%). In a third of individuals, the mental health disorder pre-dated HIV diagnosis. The researchers also found differences in the demographics of individuals in the VPCR database and those in the study sample: Clients in the database were less likely to be gay (58% versus 70%) and more likely to report injecting drug use as their HIV risk activity (24% vs 7%). Thirty-one per cent mental health disorders received treatment with potent antiretroviral therapy after 1996 compared to 26% of individuals with no recorded mental health issues. Database clients used more antiretroviral drugs (median 6.4) than individuals with good mental health (median 5.5). A third of individuals with mental health issues were hospitalized, compared to 23%with no recorded mental health disorders. The researchers also noted differences in the reasons for hospitalization between the two groups – those with mental health issues were more likely to be hospitalized because of infections (29% vs 20%), for non-infectious conditions (28% versus 19%) and for mental health reasons (18% vs 8%). Factors independently associated with an increased risk of hospitalization were mental health problems, a prior AIDS-defining illness and contracting HIV treatment prior to 1986. The researchers examined whether there was a relationship between a recorded mental health disorder and risk of death and found no difference in survival between clients in the general sample and those in the VPCR database.

HIV Medicine, May 2006, v. 7: 205–212. A. Mijch et al., Victorian HIV Psychiatry Consortium, Melbourne, Australia.

 

Binge behaviour spikes with stress

Stressed individuals might be particularly prone to binge eating or drug addiction because of high levels of a hormone mechanism in their brain, according to University of Michigan and George-town University research. Researchers injected rats with either a high dose (500ng/0.2 ml) or a low dose (250ng/ 0.2 ml) of CRF, part of the brain’s internal stress-signalling system that serves as a brain stress neurotransmitter. They injected the rats in a part of the brain called the nucleus accumbens, which is involved in the mediation of pleasurable rewards and stress signals. They observed the rats’ behaviour in response to a cue – a 30-second tone– that had previously been associated with there lease of a reward, in the form of sugar pellets. When they heard the cue, the rats pressed a lever they expected to release more sugar pellets. The authors made sure the rats did not experience stress due to CRF itself or to other factors in the experimental set-up. The results show that injection of a high dose of CRF tripled the intensity of bursts of sugar craving, measured by the pressing on the sugar-associated lever. The lever-pressing activity was only enhanced if the injection of CRF was followed by the cue; it did not increase following the injection alone. The low dose of CRF, or an empty injection, also failed to enhance the lever-pressing activity significantly. The results explain why stressed individuals might be more likely to experience strong cravings for rewards and compulsively indulge in pleasurable activities such as eating or taking drugs.

BMC Biology, April 13 2006 online, doi:10.1186/1741-7007-4-8. Susana Pecina et al., Department of Psychology, University of Michigan, Ann Arbor, Michigan.

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