Trauma-focused psychological interventions for psychosis: Meta-analytic evidence of differential effects on delusions and hallucinations

Childhood trauma is a well-established risk factor for the onset and persistence of psychotic symptoms. Consequently, trauma-focused interventions (TFIs) are increasingly incorporated into psychosis treatment, though their effectiveness in reducing hallucinations and delusions remains unclear. This systematic review and meta-analysis evaluated the effects of TFIs on psychosis-related outcomes in individuals with psychotic disorders or subclinical symptoms. Thirty-six studies (N = 1,384) were included, with 18 (N = 806) contributing to meta-analyses. Study quality and risk of bias were assessed using AXIS, Cochrane RoB 2, and GRADE. Pre–post analyses showed small reductions in hallucinations (g = –0.37; adjusted g = –0.28; K = 15) and medium reductions in delusions (g = –0.55; K = 14), with younger participants benefiting more. In controlled trials, TFIs did not significantly reduce hallucinations at end-of-treatment or follow-up (g = -0.12 and –0.01; both K=7), whereas delusions showed significant reductions at both time points (g = –0.44 and g = –0.48; both K = 7). No significant effect on negative symptoms was observed at end-of-trial (g = -0.02; K = 6), though a small improvement appeared at follow-up (g = –0.26; K = 6). TFIs produced small but significant reductions in PTSD symptoms at both time points (K = 6). No consistent effects were found for secondary outcomes: depression (K = 7), anxiety (K = 5), or quality of life (K = 3), though functioning improved at follow-up (K = 6). TFIs appear particularly effective for reducing delusions, but show limited benefit for hallucinations and other secondary outcomes. Further work is needed to design and test symptom-specific psychological interventions for distinct psychotic experiences.