title: The effects of individually tailored formulation-based cognitive behavioural therapy in auditory hallucinations and delusions: a meta-analysis.
abstract: There is no meta-analysis of cognitive behavioural therapy for delusions and hallucinations separately. The aim of this meta-analysis is to evaluate the end-of-treatment effects of individually tailored case-formulation cognitive behavioural therapy on delusions and auditory hallucinations using symptom-specific outcome measures. A systematic search of the trial literature was conducted in MEDLINE, PSYCHINFO and EMBASE. Eighteen studies were selected with symptom specific outcome measures. Hedges' g was computed and outcomes were pooled meta-analytically using the random-effects model. Our main analyses were with the selected studies with CBT using individually tailored case-formulation that aimed to reduce hallucinations and delusions. The statistically significant effect-sizes were 0.36 with delusions and 0.44 with hallucinations, which are modest and in line with other recent meta-analyses. Contrasted with active treatment, CBT for delusions lost statistical significance (0.33), but the effect-size for CBT for hallucinations increased (0.49). Blinded studies reduced effect-size in delusions (0.24) and gained some in hallucinations (0.46). There was no heterogeneity in hallucinations and moderate heterogeneity in delusion trials. We conclude that CBT is effective in treating auditory hallucinations. CBT for delusions is also effective, but the results must be interpreted with caution, because of heterogeneity and the non-significant effect-sizes when compared with active treatment.
authors.affiliation: VU University Amsterdam, Department of Clinical Psychology, Amsterdam, The Netherlands; EMGO+ Institute of Health and Care Research, Amsterdam, The Netherlands; Parnassia Psychiatric Institute, Department of Psychiatry, The Hague, The Netherlands. Electronic address: m.vander.gaag@vu.nl.
authors.forename: Mark
authors.initials: M
authors.lastname: van der Gaag
authors.affiliation: Department of Psychology, King's College London, Institute of Psychiatry, London, United Kingdom; Outreach and Support in South London (OASIS), South London and Maudsley NHS Foundation Trust, United Kingdom.
authors.forename: Lucia R
authors.initials: LR
authors.lastname: Valmaggia
authors.affiliation: VU University Amsterdam, Department of Clinical Psychology, Amsterdam, The Netherlands; EMGO+ Institute of Health and Care Research, Amsterdam, The Netherlands; Trimbos Institute (Netherlands Institute of Mental Health and Addiction), Centre for Prevention and Early Intervention, Utrecht, The Netherlands; VU University Medical Centre, Department of Epidemiology and Biostatistics, Amsterdam, The Netherlands.
authors.forename: Filip
authors.initials: F
authors.lastname: Smit
mesh_terms: D015928:Cognitive Behavioral Therapy; D003702:Delusions / Q000628:therapy*; D006212:Hallucinations / Q000628:therapy*; D006801:Humans
keywords: Cognitive behavioural therapy; Delusions; Hallucinations; Meta-analysis; Schizophrenia