Research update

CrossCurrents

Mark de la Hey

Bipolar disorder affects work more than depression

A recent study from the University of Toronto suggests that, while any mood disorder negatively affects workplace function, the negative impact of bipolar disorder on workplace function greatly exceeds that resulting from major depressive disorder. Researchers examined survey data on 20,747 currently employed individuals from the 2002 Canadian Community Health Survey: Mental Health and Well-Being. They found that individuals with either bipolar I disorder or major depressive disorder had significantly lower incomes than those without a mood disorder. However, those with bipolar disorder were at the greatest disadvantage, earning an average of $32,000 a year, nearly $5,000 less than those with major depressive disorder, who averaged $36,800 a year. Those without a mood disorder had average annual incomes of $40,200. Individuals with bipolar disorder were 60 per cent more likely than those with major depressive disorder to have reported a disability day in the previous two weeks and 40 per cent less likely to report good job security. The authors conclude that, while the overall cost to society of major depressive disorder is greater due to the higher prevalence of that disorder, their study shows that bipolar disorder is a more costly disorder at the individual level. Screening and intervention programs for people with bipolar disorder may therefore be more cost effective than comparable programs for people with major depressive disorder.

Chronic Diseases in Canada, 2008, v. 28(3): 84–91. Roger S. McIntyre et al., Department of Psychiatry and Pharmacology, University of Toronto, Toronto, Ontario.

Genetic component of fears changes during youth

The genetic component of common fears changes considerably during an individual’s passage through childhood and adolescence, according to new research from the Virginia Commonwealth School of Medicine in Richmond, Virginia. A sample of 2,490 Swedish twins and their parents was questioned regarding the intensity of the twins’ situational fears, animal fears and blood/injury fears between age 8 and 20. It turned out that some genetic risk factors influenced the intensity of fears at age 8 and 9 and then became less influential as the children aged, while new genetic risk factors “came on line” in adolescence and early adulthood. In addition, the influence of the children’s shared environment on their fears decreased and that of each child’s unique environment increased during adolescence. This reflects the fact that the role of the home environment typically declines during adolescence as children spend progressively less time with family and more time with friends. According to the authors, these results support a “develop­mentally dynamic” hypothesis predicting that the influence of genetic factors on our fears will vary over time. This can result from both genetic innovation, whereby new genes become active over time, and genetic attenuation, whereby the influence of some genes declines with the passage of time. The authors explain that this genetic dynamism may have evolved in response to the reality that threats posing the greatest risk to a young child are not necessarily the same as those that most threaten an adolescent or adult.

Archives of General Psychiatry, April 2008, v. 65: 421–429. Kenneth S. Kendler et al., Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University Medical School, Richmond, Virginia.

Counselling by pediatric providers and peers reduces teen smoking

Counselling by pediatric care providers and peer counsellors can be effective in preventing adolescents from taking up smoking and getting those who are already smokers to quit, according to a new study from the University of Massachusetts Medical School in Worcester, Massachusetts. Over the course of twelve months, researchers followed 2711 smoking or non-smoking patients between the ages of 13 and 17 who visited one of eight Massachusetts pediatric primary care clinics. Participants were randomly assigned to either usual care or an intervention that consisted of a brief counselling visit with a pediatric care provider followed by counselling from peer counsellors aged 21 to 25 years during the initial six months. Compared with those given usual care, non-smokers who received counselling from both physicians and peers were 2.2 times as likely to have remained abstinent at six months and 1.6 times as likely to have done so at twelve months. Among smokers, those given the combination of provider and peer counselling were 1.6 times as likely as those given usual care to have quit at six months, but there was no difference between the two groups at 12 months. Smokers who paid more frequent visits to their doctors were more likely to have quit at the six and twelve month follow-ups. Encouraged by these results, the authors suggest that extending peer counselling beyond the initial six months might improve rates of abstinence among smokers at 12 months.

Pediatrics, April 2008, v. 121, online, doi: 10.1542/peds.2007–1029. Lori Pbert et al., Division of Preventive and Behavioral Medicine, University of Massachusetts Medical School, Worcester, Massachusetts.

Binge drinking more common than alcohol dependence in impaired driving

Binge drinkers are more likely to be responsible for alcohol impaired driving than people with alcohol dependence, say researchers with the U.S Centers for Disease Control and Prevention in Atlanta, Georgia. The researchers analyzed results from the 2006 Behavioral Risk Factor Surveillance System survey, looking at data with respect to alcohol consumption and self-reported impaired driving among 157,914 U.S. adults who were current drinkers. For the purposes of this study, binge drinking was defined as the con­sumption of four or more drinks per occasion among women and five or more drinks per occasion among men. Heavy drinking was defined as the consumption of an average of more than one drink a day among women and more than two drinks among men. The researchers found that 84 per cent of those who drove while alcohol impaired were binge drinkers. Binge drinkers who were also heavy drinkers were 20 times more likely than those who were neither binge drinkers nor heavy drinkers to drive while impaired. Impaired driving was also eight times as likely among binge drinkers who were not heavy drinkers and four times as likely among heavy drinkers who did not binge drink, compared with those who were neither binge drinkers nor heavy drinkers. These results suggest that the majority of impaired drivers are not alcohol dependent, and are therefore likely to be responsive to alcohol control policies and counselling by health care providers.

Alcoholism: Clinical and Experimental Research, April 2008, v. 32: 639–644. Nicole T. Flowers et al., Division of Adult and Community Health, Centers for Disease Control and Prevention, Atlanta, Georgia.

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