RESUMO
BACKGROUND: One in five young people with first-episode psychosis (FEP) also presents with borderline personality disorder (BPD) features. Among people diagnosed with BPD, auditory verbal hallucinations occur in 29-50 % and delusions in 10-100 %. Co-occurrence of psychotic symptoms and BPD is associated with greater clinical severity and greater difficulty accessing evidence based FEP care. This study aimed to investigate psychotic symptoms and psychosocial functioning among young people presenting to an early intervention mental health service. METHOD: According to the presence or absence of either FEP or BPD, 141 participants, aged 15-25 years, were assigned to one of four groups: FEP, BPD, combined FEP + BPD, or clinical comparison (CC) participants with neither FEP nor BPD. Participants completed semi-structured diagnostic interviews and interviewer and self-report measures of psychopathology and psychosocial functioning. RESULTS: The FEP + BPD group had significantly more severe psychopathology and poorer psychosocial functioning than the FEP group on every measure, apart from intensity of hallucinations. Comparing the FEP or BPD groups, the BPD group had greater psychopathology, apart from intensity of psychotic symptoms, which was significantly greater in the FEP group. These two groups did not significantly differ in their overall psychosocial functioning. Compared with CC young people, both the FEP + BPD and BPD groups differed significantly on every measure, with medium to large effect sizes. CONCLUSIONS: Young people with co-occurring FEP and BPD experience more severe difficulties than young people with either diagnosis alone. This combination of psychosis and severe personality pathology has been longitudinally associated with poorer outcomes among adults and requires specific clinical attention.