Predictors of engagement and response in cognitive behaviour therapy for psychosis: A systematic review.

AIM: Cognitive Behavioural Therapy for psychosis (CBTp) is a recommended psychosocial treatment for psychosis, yet a substantial proportion of individuals do not engage with therapy or fail to achieve meaningful treatment gains. METHOD: A systematic review was conducted to summarise the existing literature regarding the predictors of treatment response to, and engagement with, CBTp across the psychosis continuum (i.e., Clinical High Risk for psychosis [CHR], First Episode Psychosis [FEP], and schizophrenia [SZ]). RESULTS: Twenty-three studies were included (N = 3241, FEP = 3; SZ = 20; CHR = 0). The review identified substantial heterogeneity in study design, outcome measures and findings. Some studies reported associations between lower delusional conviction and higher levels of insight with more favourable outcomes, while longer illness duration was associated with poorer outcomes in some studies, although none of these associations were consistently replicated. Symptom severity showed heterogeneous associations with CBTp response. Engagement findings were limited, with lower negative symptom severity associated with better uptake or engagement in some studies. Some evidence suggested that poorer engagement may be associated with behavioural and occupational difficulties. Evidence for associations with socio-demographic and medication-related factors, functioning, belief flexibility, depression/anxiety, and neurocognitive predictors was limited, inconsistent, or null. CONCLUSIONS: The available evidence does not allow definitive conclusions about the factors associated with CBTp engagement and outcome. The findings suggest that these outcomes may be influenced by a combination of clinical factors and psychological processes. Further research is needed to establish robust and generalisable predictors, particularly in early psychosis.