Pubertal timing in girls and depression: a systematic review.

BACKGROUND Because the incidence of depression increases after puberty, it is possible that pubertal timing in girls influences the onset of depression. Our objective was to assess the effect of early and late puberty in girls on the incidence of depression. METHODS We systematically searched relevant databases for controlled studies that assessed the impact of pubertal timing in girls on the incidence of depression or depressive symptoms. The last search was completed in August 2013. Two authors selected the studies, extracted the data, and assessed the quality of the evidence. Meta-analyses of the adjusted and unadjusted results were calculated using random effects. RESULTS Four cohort studies were included (n=8055 participants). Early puberty significantly increased the risk of new cases of depression in the unadjusted meta-analysis (RR=1.33; CI 95%: 1.02, 1.73) but not in the adjusted estimate of two of the included studies (RR=1.48; CI 95%: 0.69, 2.28). For late puberty, no significant associations were found (unadjusted RR=1.28; CI 95%: 0.87, 1.88). Two studies assessed the effect of early puberty on depressive symptoms and found positive associations. The quality of the available evidence was rated as very low. LIMITATIONS The polled results had wide confidence intervals, and the available evidence was of very low quality. CONCLUSIONS The available evidence supports little confidence regarding the impact of pubertal timing on the onset of depression in girls but suggests that early puberty in girls may increase the risk of depression. Further higher quality studies are needed to clarify the association between pubertal timing and the incidence of depression in girls and women.