Associations Between Common Forms of Psychopathology and Fecundity: Evidence From a Prospective, Longitudinal Twin Study

We examined associations between common psychiatric disorders and fecundity in a population-based cohort of 1,252 twins prospectively assessed from adolescence into adulthood. Major depressive disorder, anxiety disorders, and alcohol use disorders were associated with lower likelihood of having children and having fewer children. Survival analyses yielded similar results accounting for timing and recurrence. Although both early- and adult-onset psychiatric disorders were associated with decreased fecundity, early-onset major depressive disorder, anxiety disorders (among boys), and alcohol use disorders (among girls) were associated with greater likelihood of having a child during adolescence. Among twin pairs discordant for psychiatric disorders (i.e., one twin affected and one twin unaffected by major depressive disorder, anxiety disorders, or alcohol use disorders), twins affected by anxiety and alcohol use disorders but not major depressive disorder were less likely to have children than their unaffected co-twins. However, unaffected twins with an affected co-twin were no more likely to have children than twins from unaffected twin pairs, inconsistent with the balancing-selection hypothesis that increased fecundity in unaffected relatives accounts for persistence of psychiatric disorders.