Personality disorders in depressed adolescent outpatients: Impact on outcome and treatment of depression, changes in symptoms, and predictors into young adulthood

Background. Personality disorders (PDs) among depressed adolescents are common, but there is little research on how PDs impact the course of depression and the long-term development from adolescence into adulthood. The objective of this study was to examine the association between depression and PDs in a one-year follow-up of adolescents and in an eight-year follow-up from adolescence to adulthood, PD symptom change during adolescence, and the associations of PDs with defense mechanisms, social support, and comorbid psychiatric disorders among depressed adolescents. Methods. This study was part of the Adolescent Depression Study (ADS), a prospective, naturalistic research project. The sample comprised originally depressed adolescent outpatients (N=218) aged 13–19 years, who were interviewed and diagnosed at baseline and at six-month and one-year follow-ups using K-SADS- PL for DSM-IV psychiatric clinical disorders and SCID-II for PD diagnoses. The subjects were further assessed in an eight-year follow-up using diagnostic interviews (SCID-I and -II) and self-report scales, and observer-report rating scales were used at every assessment point. Results. Of the participants, 67% presented at least one depression recurrence. At the eight-year follow-up, 36% had a mood disorder, and anxiety (48%) and PDs (26%) were also frequent.Over half of the patients suffered from a mood disorder 25% or more of the follow-up time from adolescence into adulthood. If presenting with comorbid depression and PD, the short-term outcome in psychiatric treatment was worse. Treatment breadth did not impact positively on the outcome for depressed adolescents with a PD, but those without a PD gained from a larger variety of treatments. Decrease in both depression severity and comorbidity rate correlated positively with PD symptom decrease. Higher perceived social support was associated with a decrease in PD symptoms in the PD categories narcissistic, schizotypal, and paranoid. Immature defense mechanisms predicted PDs in adulthood, while mature defense style did not associate negatively with a later PD diagnosis. Displacement, isolation, and reaction formation were the strongest predictors of a PD in adulthood, all considered mental inhibitions. Conclusion. These results show the seriousness of depression in adolescence and its long-term impact on outcome. In patients presenting with a comorbid PD, the short- and long-term outcomes of depression were generally worse. Social support and thus the ability to connect with other people might impact clinical symptoms, higher perceived social support being a possible protective factor for symptoms. There was covariation between symptoms of PDs and other psychiatric symptoms, all clinically relevant in treatment planning. Adolescents with PD should be treated with specialized treatments for PDs. In line with earlier studies, the results suggest defense styles should be a focus in treatment planning and content. Also, attention should be directed to separate defenses, especially those having to do with mental inhibition.