Possible genetic link between eating disorders and seasonal changes in mood and behavior

Polymorphism of the 5-HT2A receptor gene and food intakes in children and adolescents: the Stanislas Family Study

BACKGROUND

Serotonin (5-hydroxytryptamine; 5-HT) is a key mediator in the control of food intake and is probably involved in the etiology of anorexia nervosa. An association between a polymorphism of the 5-HT receptor (5-HT2A) gene promoter (-1438G/A) and anorexia nervosa has been reported.

OBJECTIVE

We investigated the relation between the -1438G/A polymorphism of the 5-HT(2A) gene and the energy and macronutrient intakes of children and adolescents.

DESIGN

This cross-sectional study included 370 children and adolescents aged 10-20 y (176 boys and 194 girls from 251 families) drawn from the Stanislas Family Study. Energy and macronutrient intakes were assessed by using 3-d food records. The -1438G/A polymorphism was analyzed by polymerase chain reaction and then by Hpa II digestion.

RESULTS

In the overall group, after adjustment for age, sex, weight, height, and family correlation, the A allele was significantly associated with lower energy (P for trend = 0.045) and with total, monounsaturated, and saturated fat intakes expressed in g/d (P for trend = 0.007, 0.005, and 0.006, respectively). Subjects with the GA genotype had intermediate values. In addition, genotype x sex and genotype x age interactions were not significant.

CONCLUSIONS

The 5-HT2A gene polymorphism in the promoter region is associated with energy and fat intakes in young people. This could be explained by the role of the serotonergic system as a determinant of food intakes and eating behavior.

Alcoholism and seasonal affective disorder

Seasonal changes in mood and behavior (seasonality) may be closely related to alcoholism. Some patients with alcoholism have a seasonal pattern to their alcohol misuse. They may be self-medicating an underlying seasonal affective disorder (SAD) with alcohol or manifesting a seasonal pattern to alcohol-induced depression. Both genetic and environmental factors play a role in the etiology and pathogenesis of alcoholism and SAD, operating, at least in part, through the brain serotonergic system. Family and molecular genetic studies suggest that there may be a genetic link between seasonality and alcoholism. Certain environmental and social factors may contribute to the development of seasonality in patients with alcoholism. The fact that SAD and alcoholism may be comorbid shows the importance of a thorough diagnostic interview. Both mental health and drug and alcohol professionals should be provided with education to assist with appropriate identification, management, and referral of patients presenting with comorbid alcoholism and SAD.