Individual CBT for psychosis
Individual cognitive work for psychosis is most like psychotherapy for other disorders in that outpatients are seen weekly or fortnightly for up to an hour by a therapist. As with FI, CBT should be used in addition to a range of other community, social, and vocational support interventions and in combination with optimal antipsychotic medication. Current evidence shows that low-dose typical antipsychotics can be as effective as atypical medications26,27 but that up to 40% of those with psychosis may still have distressing positive symptoms. Those with distressing, ongoing positive symptoms, despite adequate medication (typical or atypical), are the group to whom considerable psychotherapeutic effort has been targeted and which continues to have the best evidence for outcome so far.1,4,28,29
The evidence base for the use of CBT for psychosis is still developing, with many studies based in the United Kingdom. Given the pessimistic therapeutic climate associated with schizophrenia, early studies concentrated on dealing with distress and ensuring that therapy did not make things worse.30-36 Initial studies showed that supportive therapy was helpful, even if its effects were not usually long-lasting. Other studies looked at intervention in acute conditions,37 in early episodes with brief treatment for acute states,38 in relapsing groups,39 with brief treatment offered by frontline community staff and not by “experts,”40 and specifically for those with auditory hallucinations.41
Effect sizes remained moderate at 0.37 in the meta-analyses by Tarrier and Wykes28 and Zimmermann and colleagues29; and 0.47 in Pfammatter and colleagues' analysis.1 One longer-term follow-up study of 2 trials found that gains did not tend to continue and that as few as 10% maintained symptomatic improvements more than 2 years after treatment.42 Tarrier and Wykes28 have criticized the methodology of early trials and claimed that better results were to be found in poorer-quality trials; other investigators have disagreed.29
Overall, evidence is accumulating that, particularly for those with persistent symptoms, specifically delusions, longer treatment duration may reduce symptoms, at least in the medium term.1,4 For persistent hallucinations, there is some evidence that changing beliefs can reduce distress.41
In trials of CBT with prodromal groups (patients with a relatively high risk of transition to psychosis), the evidence is more tentative. A study by McGorry and colleagues43 has shown no real changes with CBT and medication in reducing transition to psychosis over the longer term. In their study, Morrison and colleagues44,45 offered CBT alone and found early indications that this can be helpful, but the rate of transition to psychosis (around 20%) was not high for either the intervention or control group. Some studies have shown that relapse rates46 and social functioning47 can be improved with early intervention (after one episode of psychosis) and that both intervention and control groups improve over time,48 while others have shown reduced transition rates but no long-term clinical effects.49
