The efficacy of acceptance and commitment therapy (ACT) in psychosis has been reported but not for medication-resistant psychosis.

To test the efficacy of ACT in a sample of community-residing patients with persisting psychotic symptoms. (Australian New Zealand Clinical Trials Registry: ACTRN12608000210370.)

The primary outcome was overall mental state at post-therapy (Positive and Negative Syndrome Scale –total); secondary outcomes were psychotic symptom dimensions and functioning. In total, 96 patients were randomised to ACT (n = 49) or befriending (n = 47). Symptom, functioning and process measures were administered at baseline, post-therapy and 6 months later.

There was no group difference on overall mental state. In secondary analyses the ACT group showed greater improvement in positive symptoms and hallucination distress at follow-up: Cohen's d = 0.52 (95% CI 0.07–0.98) and 0.65 (95% CI 0.24–1.06), respectively.

Improvements reflected the treatment focus on positive symptoms; however, absence of process-measure changes suggests that the ACT intervention used did not manipulate targeted processes beyond befriending. Symptom-specific therapy refinements, improved investigation of process and attention to cognitive functioning and dose are warranted in future research.

There is conflicting evidence about comorbid personality pathology in depression treatments.

To test the effects of antidepressant drugs and cognitive therapy in people with depression distinguished by the presence or absence of personality disorder.

Random assignment of 180 out-patients with depression to 16 weeks of antidepressant medication or cognitive therapy. Random assignment of medication responders to continued medication or placebo, and comparison with cognitive therapy responders over a 12-month period.

Personality disorder status led to differential response at 16 weeks; 66% v. 44% (antidepressants v. cognitive therapy respectively) for people with personality disorder, and 49% v. 70% (antidepressants v. cognitive therapy respectively) for people without personality disorder. For people with personality disorder, sustained response rates over the 12-month follow-up were nearly identical (38%) in the prior cognitive therapy and continuation-medication treatment arms. People with personality disorder withdrawn from medication evidenced the lowest sustained response rate (6%). Despite the poor response of people with personality disorder to cognitive therapy, nearly all those who did respond sustained their response.

Comorbid personality disorder was associated with differential initial response rates and sustained response rates for two well-validated treatments for depression.