background A single episode of major depressive disorder (mdd) may be incidental and might differ from multiple episodes in terms of burden of disease. No study to date separately explored risk factors for a single episode or for multiple episodes of mdd in primary care.
aim To examine the risk factors for a single episode or for multiple episodes of mdd in primary care.
methods Prospective cohort study of 1338 consecutive attendees with follow-up after six, 12 and 39 months with dsm-iv mdd diagnoses. Depressive episodes were counted and categorised in 0, 1 and 2 or more episodes. Log-binomial regression was performed with the risk factors as independent and number of depressive episodes as dependent variable, adjusted for age, sex and lifetime depression.
results 169 participants had one episode and 102 had two or more episodes of mdd in 39 months. Compared to a single episode, risk factors for having two or more episodes were recent difficulties (rr 1.9; 95% ci 1.2-2.8), more severe depressive symptoms (rr 5.3; 95% ci 2.2-12.3), lifetime depression (rr 1.4; 95% ci 1.0-2.0), suicide in first degree relatives (rr 1.6; 95% ci 1.0-2.7), divorced parents (rr 1.5; 95% ci 1.0-2.2), feelings of loneliness as child (rr 1.5; 95% ci 1.1-2.1), chronic difficulties (rr 1.6; 95% ci 1.1-2.3), low social support (rr 1.5; 95% ci 1.1-2.1), and difficulties in relationships (rr 1.4; 95% ci 1.0-1.9).
conclusion Nearly all explored factors increased the risk for depressive episodes when compared to no episodes. Vulnerability, illnessrelated and stress factors were associated with having multiple episodes when compared to a single episode, while socio-demographic and comorbidity factors were not.