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 (<i>N</i> = 1,384) were included, with 18 (<i>N</i> = 806) contributing to meta-analyses. Study quality and risk of bias were assessed using AXIS, Cochrane RoB2, and GRADE. Pre-post analyses showed small reductions in hallucinations (<i>g</i> = -0.37; adjusted <i>g</i> = -0.28; <i>K</i> = 15) and medium reductions in delusions (<i>g</i> = -0.55; <i>K</i> = 14), with younger participants benefiting more. In controlled trials, TFIs did not significantly reduce hallucinations at the end of treatment or follow-up (<i>g</i> = -0.12 and -0.01; both <i>K</i> = 7), whereas delusions showed significant reductions at both time points (<i>g</i> = -0.44 and <i>g</i> = -0.48; both <i>K</i> = 7). No significant effect on negative symptoms was observed at the end of trial (<i>g</i> = -0.02; <i>K</i> = 6), though a small improvement appeared at follow-up (<i>g</i> = -0.26; <i>K</i> = 6). TFIs produced small but significant reductions in PTSD symptoms at both time points (<i>K</i> = 6). No consistent effects were found for secondary outcomes: depression (<i>K</i> = 7), anxiety (<i>K</i> = 5), or quality of life (<i>K</i> = 3), though functioning improved at follow-up (<i>K</i> = 6). TFIs appear particularly effective in 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.