Characteristic | Major depressive disorder (DSM-IV) | No major depressive disorder | p value |
---|---|---|---|
Total number of subjects | 153 | 344 | |
Familial depression b | 67 (43.8%) | ||
Gender | |||
Male | 63 (41.2%) | 190 (55.2%) | |
Female | 90 (58.8%) | 154 (44.8%) | <0.01 c |
Age (mean ± SD years) | 37.1 ± 11.3 | 37.7 ± 12.0 | 0.58 d |
Lifetime marijuana dependence | 21 (13.7%) | 12 (3.5%) | <0.01 e |
Lifetime alcohol dependence or abuse | 121 (79.1%) | 188 (54.7%) | <0.01 e |
↵ a Excludes 48 individuals who were not analyzed because of insufficient DNA. Numbers in parentheses denote percentage of total number of subjects in respective category.
↵ b A diagnosis of familial depression is assigned when individuals exhibit both a diagnosis of DSM-IV major depression and at least one of their first-degree family members is ascertained to have been depressed through the interview of the proband.
↵ c Comparison between proportions of males and females in the categories of major depressive disorder (DSM-IV) and no major depressive disorder (χ 2).
↵ d Comparison between categories of major depressive disorder (DSM-IV) and no major depressive disorder (Student's t test).
↵ e Comparison between proportions of subjects in the categories of major depressive disorder (DSM-IV) and no major depressive disorder (χ 2).