Borderline personality disorder (borderline) is characterized by mood swings, self-mutilation, impulsive behavior, and thinking in black-and-white terms. Though even adolescents may suffer from borderline, few assessment instruments and treatment methods are available for this age-group.

We developed an interview to examine severity of borderline symptoms in adolescents, by comparing 122 adolescents with borderline symptoms to 45 healthy controls. We found that borderline symptoms cannot be seen as normal phenomena in adolescence. There is a clear distinction between borderline symptoms and normal development.

Next, we developed the Emotion Regulation Training (ERT), a 17-week group training for adolescents with borderline. ERT aims at improvement of locus-of-control and management of ‘emotional storms’. The results of a pilot study with 43 adolescents were promising. However, in a larger randomized controlled trial with 109 adolescents, we found no additional value of ERT above treatment as usual.

Further, we explored parental factors that may contribute to the developmental pathways of borderline. Compared to healthy controls, adolescents with borderline symptoms were more frequently raised by mothers with psychiatric complaints. Also, mothers of youth with borderline symptoms were more overprotective and less emotionally warm in their parenting styles compared to mothers of the control group. Higher levels of parenting stress were associated with higher levels of overprotection in mothers of adolescents with borderline symptoms.

There is a need for age-specific treatments for adolescent BPD. Early interventions that include a systemic approach may prevent the adverse outcome in the long-term.