RESUMO
BACKGROUND: Group differences in longitudinal patterns of child and adolescent depressive symptoms are commonly observed. However, the implications for adult mental health are unclear. This study presents a systematic review of child and adolescent depressive symptom trajectory research and meta-analysis of their longitudinal effects on adult depressive symptoms and disorders. METHODS: A systematic search identified 12 longitudinal studies (12 cohorts, N = 35,058) that were harmonized to identify common symptom trajectories prior to age 18 years. Examination of follow-up in the same groups was made (at average age 20.5 years) to estimate longitudinal associations with adult depressive symptoms (Sx) and disorders (Dx), using random effects meta-analyses. RESULTS: The included studies identified Low (70.3 %), Moderate (17.9 %), High (9.5 %), Increasing (9.5 %) and Decreasing (5.1 %) symptom trajectories. These trajectories were found to predict variation in symptoms and disorders in adulthood: Low, Dx = 4.5 %, 95 % Confidence Interval [CI] 2.7-6.8 %, Sx [Mean] = 8.33, Standard Deviation [SD] = 6.30; Moderate, Dx = 20.9 %, CI 11.9-31.5 % - Sx = 18.13, SD = 3.38; High, Dx = 34.4 % CI 17.2-54.0 % - Sx = 38.80, SD = 7.75; Increasing, Dx = 38.3 %, CI 12.7-67.5 % - Sx = 24.73, SD = 18.64; Decreasing, Dx = 15.4 %, CI 10.5-20.9 % - Sx = 17.00, SD = 12.18. LIMITATIONS: Confidence intervals are wide for some trajectory effects. There was significant between-cohort heterogeneity in predictive effects for High trajectories, suggesting the need for further research to identify characteristics influencing variation. CONCLUSION: Low symptom trajectories forecast lower adult depression symptoms and disorders. Programs effectively targeting reductions in Moderate, High, Increasing and Decreasing trajectories will likely prevent problems in early adulthood.