Children at risk for depression: memory biases, self-schemas, and genotypic variation.

Background: Daughters of depressed mothers are at increased risk for developing a depressive disorder. We know relatively little, however, about the specific factors that contribute to this elevated risk. The present study investigated the effects of familial risk for depression and the 5-HTTLPR and COMT Val158Met polymorphisms, which have been associated with risk for depression, on biases in endorsement of and memory for positive and negative adjectives.

Methods: Following a negative mood induction, 60 girls between the ages of 10 and 14 who had recurrent depressed mothers (high risk for depression) and 91 age-matched daughters of never-disordered mothers (low risk for depression) completed a Self-Referent Encoding Task in which they decided whether negative and positive adjectives described them. Following the task they were asked to recall as many of the adjectives as they could.

Results: Despite the absence of significant group differences in endorsement of positive or negative adjectives, high-risk girls with the COMT Val158Met Val/Val polymorphism recalled more positive (but not negative) words that they had endorsed than did high-risk girls who were homozygous for the Met allele. COMT was not associated with recall of valenced adjectives in low-risk girls. Across risk groups, 5-HTTLPR polymorphism was not associated with recall of valenced adjectives.

Limitations: Even with over 150 participants, there were relatively small numbers in some of the cells of this study, limiting its statistical power.

Conclusions: These results suggest that assessing the interaction of familial risk status and COMT polymorphism is important in understanding the development of depressive disorders.