Personality functioning and maladaptive traits in social anxiety disorder: associations with symptom severity and change following intensive iCBT

Abstract Previous research has established links between personality disorder and social anxiety disorder (SAD), but less is known about broader personality pathology, including personality functioning and maladaptive traits in relation to SAD and its treatment. This study investigated the dimensional components of the DSM-5 Alternative Model for Personality Disorders (AMPD) in adults with primary SAD ( N = 59) completing intensive internet-delivered cognitive behavioural therapy (iCBT). Participants completed measures of personality functioning (LPFS-BF), maladaptive traits (PID-5-BF), social anxiety (SIAS, SPS), depressive symptoms (PHQ-9), and psychosocial functioning (WSAS), alongside diagnostic interviews (ADIS-5) for SAD and Major Depressive Disorder (MDD), at baseline and after completing intensive iCBT. At baseline, participants showed mild impairments in personality functioning and largely non-clinical levels of maladaptive traits, with greater impairment among those with comorbid MDD. Greater impairment in personality functioning, particularly self-functioning, and higher maladaptive trait severity (including negative affectivity, disinhibition, and psychoticism) were associated with greater social anxiety severity. After controlling for baseline symptom severity, personality pathology was not significantly associated with post-treatment social anxiety, depressive symptoms or psychosocial impairment. Significant reductions in personality functioning and maladaptive trait severity were observed following intensive internet-delivered cognitive behavioural therapy (iCBT); however, this may not be indicative of enduring personality change. Taken together, these preliminary findings suggest that personality pathology is clinically relevant in SAD and is associated with symptom severity, but it does not independently predict short-term treatment outcomes after accounting for baseline symptom severity. Overall, the results support the utility of dimensional models of personality pathology in understanding social anxiety. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12622000361707 (1 st March 2022).