Untangling Influences in the Longitudinal Relationship Between Depressive Symptoms and Drinking Frequency in High School.

Purpose: In young people, alcohol consumption and depressive symptoms are related, but the temporal ordering of the relationship is an open question. Previous studies have not disaggregated influences of interindividual and intraindividual components affecting the relationship. We investigated whether a reciprocal relationship between frequency of alcohol use and depressive symptoms exists in the general population of adolescents after removing interindividual influences.

Methods: A total of 1,293 Canadian adolescents provided data on depressive symptoms and frequency of alcohol use every 3 months from grade 7 to 11 (1999-2005) for a total of 20 cycles. We used latent curve models with structured residuals, which disaggregate interindividual and intraindividual components to assess the directionality of the relationship.

Results: Both drinking frequency and depressive symptoms increased linearly and quadratically over time, with significant interindividual variation around the origin and rate of change. Intercepts and slopes for drinking frequency and depressive symptoms differed by sex and age. After controlling for sex, age, maternal education, sensation seeking, impulsivity and clustering by school, a significant positive association was observed between depressive symptoms and drinking frequency 3 months later (.032 [.004, .060]; p = .024), but no association was observed between drinking frequency and subsequent depressive symptoms (.011 [-.006 to .029]; p = .193).

Conclusions: Our data provide longitudinal evidence that changes in depressive symptoms exceeding one's "normal" level predict increases in drinking frequency. This suggests that teaching youth to recognize and cope with mood changes would be worthwhile.