# Mixed features and suicide attempts in youth depression: a six-month follow-up study

## TL;DR

This study finds that mixed features during depression increase the risk of suicide attempts in young people, especially those experiencing their first depressive episode.

## Contribution

The study provides new evidence that mixed features are a risk factor for suicide attempts in adolescents and young adults with depression.

## Key findings

- 33.2% of participants had mixed features during their depressive episodes.
- Mixed features were associated with a higher risk of suicide attempts, particularly at 6 months.
- The effect was strongest in individuals experiencing their first depressive episode.

## Abstract

Mixed features during major depressive episodes (MDE) may confer elevated suicide risk, yet evidence in adolescents and young adults remains limited. This study aimed to investigate the association between mixed features and suicide attempts in this population.

We conducted a prospective cohort study including 951 adolescents and young adults (aged 13–25 years) with MDE, recruited from multiple hospitals in South China (2022–2023). Mixed features were defined as ≥ 3 (hypo)manic symptoms during depression. Baseline suicidal risk was assessed using item 3 of the Hamilton Depression Rating Scale (HAMD-17). Follow-up suicide attempts were assessed at 1, 3, and 6 months via structured interviews. Cox proportional hazards models evaluated time to first suicide attempt, with multiple imputation applied for missing data. Subgroup analyses examined effect modification by sex, episode status, age, and illness duration.

Of 951 participants, 316 (33.2%) met criteria for mixed features. Participants with mixed features had a higher incidence of suicide attempts during follow-up, reaching significance at month 6 (p = 0.032). Cox regression showed that mixed features were associated with an increased hazard of suicide attempts (HR = 1.32, p = 0.045; complete-case analysis HR = 1.89, p = 0.039). Baseline depressive severity and suicidal ideation independently predicted risk. Subgroup analyses showed a significantly stronger effect among participants in their first depressive episode. Participants with shorter illness duration also exhibited the highest hazard ratio, although the interaction did not reach conventional significance.

Mixed features were associated with an increased risk of suicide attempts in adolescents and young adults with depression, with the effect being most evident in first-episode patients. Systematic assessment of mixed features may help identify individuals who would benefit from early and tailored preventive strategies.

Not applicable.

The online version contains supplementary material available at 10.1186/s12888-026-07783-x.