Relevance between age of onset and hospitalization characteristics of Major Depressive Disorders: A 16 years...

Age of onset (AOO) influences the prognosis of many diseases and even serves as potential driver. But in Major Depressive Disorder, there is no consensus regarding the effect of AOO on the course.

In this study, a total of 38,671 inpatients were surveyed over 16 years, and 6113 inpatients were eventually included in the statistical analysis after applying rigorous data criteria. Inpatients were divided into four AOO subgroups: adolescent onset, early adult onset, middle adult onset, and late adult onset.

In the subset of first hospitalization (n = 4884), the differences in the length of stay between several AOO subgroups were statistically significant (F = 56.852, df₁ = 3, df₂ = 4880, P < 0.001, ω² = 0.033). Similarly, this difference was also significant in the subset of relapse hospitalization (n = 1229, F = 5.985, df₁ = 3, df₂ = 1225, P < 0.001, ω² = 0.012). The Bonferroni post hoc test suggested a longer length of stay in the adolescent onset group (P < 0.001). Besides, in the adolescent onset subgroup, the proportion with 2 or more relapses hospitalization within one year was higher than those without relapses (6.7 % Vs 2.7 %, χ² = 12.685, df = 6, P < 0.001). Logistic regression suggests that patients with adolescent onset are at higher risk for 2 or more relapses hospitalization within one year (B = 0.881, OR = 2.41, 95 % CI 1.37-4.23, P = 0.002).

Retrospective design may have recall bias.

This is the first large sample size study to examine age at onset and risk of relapse at the individual level in a Chinese population. Our study found that adolescent onset is more susceptible to the chronicity of MDD. These findings will contribute to the accurate typing of MDD, as well as customized individualized prevention and treatment options.