Which Psychosocial Risks Are Necessary for Developing Depression During Adolescence? A Novel Approach Applying Necessary Condition Analysis

Objective: Although many factors predict adolescent depression, risks that operate as necessary conditions (ie, absence of the factor conveys absence of the outcome) have been largely unexplored. This study aimed to evaluate which psychosocial risk factors might serve as necessary conditions for future onset of depression across adolescence. Method: At baseline, cognitive and personality risks, symptom severity, stressful events, and past depression history were assessed among 382 adolescents (225 girls; mean age = 12.6), who were then followed over 2 years with repeated diagnostic interviews to ascertain depression onset. An innovative statistical approach in mental health research, necessary condition analysis, was applied. Results: Baseline rumination (d = 0.50), stressful events (d = 0.37), depressive symptoms (d = 0.23), and self-criticism (d = 0.35) all emerged as significant necessary conditions for adolescents to be diagnosed with a depressive disorder over the subsequent 24 months. Overall, 13.5% of the sample did not show all the necessary conditions (ie, they lacked 1 or more conditions) and were therefore virtually immune from experiencing 1 or more major depressive episodes over the follow-up, and 65.5% did not meet all those conditions for experiencing 3 or more major depressive episodes (ie, recurrent depression). Conclusion: These findings can inform future theory building and testing as well as clinical applications via screening of necessary risk to future pediatric depression so that youth who may most benefit from effective interventions can be identified. Plain language summary: This longitudinal study explored which factors are necessary (but not sufficient) for adolescents to develop depression. Authors analyzed data from 382 adolescents over two years and found rumination, stressful events, depressive symptoms, and self-criticism to be necessary for depression to occur. Only 13.5% of participants did not report all of these “necessary” factors and were nearly immune to developing one or more major depressive episodes (MDEs) over the follow-up. Conversely, 86.5% of the participants possessed all the necessary conditions for developing a major depressive disorder with 13.2% of these participants experiencing 1 or more MDEs over the 2-year follow-up. Study preregistration information: The Necessary Conditions for Depressive Symptoms and Major Depression in Adolescence; https://osf.io/b5ced. Diversity & Inclusion Statement: We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. We worked to ensure sex and gender balance in the recruitment of human participants. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented sexual and/or gender groups in science.