Table 2.

Effect Sizes of CBTp for Auditory Hallucinations

	N	g	95% CI	Z	Q-Value	I 2 (%)
Main comparison with all eligible RCTs
Any risk of bias score included	28	0.34**	0.20, 0.49	4.63	52.83**	49
High risk of bias (>1)a	26	0.34**	0.19, 0.49	4.43	51.12**	51
Lowest risk of bias (0)b	19	0.40**	0.22, 0.58	4.40	41.49**	59
CBTp vs TAU
Any risk of bias score included	22	0.35**	0.18, 0.52	4.00	45.94**	54
High risk of bias (>1)a	20	0.34**	0.17, 0.52	3.77	44.24**	58
Lowest risk of bias (0)b	14	0.41**	0.19, 0.63	3.65	36.90**	65
CBTp vs active intervention
Any risk of bias score included	8	0.34**	0.15, 0.53	3.58	7.03	0
High risk of bias (>1)a	8	0.34**	0.15, 0.53	3.58	7.03	0
Lowest risk of bias (0)b	5	0.42**	0.20, 0.64	3.70	4.15	4
CBTp with hallucinations as primary outcomec
Any risk of bias score included	23	0.40**	0.24, 0.56	4.90	40.42*	46
High risk of bias (>1)a	21	0.40**	0.23, 0.57	4.66	38.84**	49
Lowest risk of bias (0)b	14	0.51**	0.32, 0.70	5.22	25.67*	49
CBTp with individualized case formulationd
Any risk of bias score included	21	0.41**	0.25, 0.57	5.03	39.86*	50
High risk of bias (>1)a	20	0.42**	0.26, 0.59	5.02	39.44*	52
Lowest risk of bias (0)b	15	0.45**	0.25, 0.65	4.47	39.98**	62
CBTp with individualized CF + primary outcomec,d
Any risk of bias score included	16	0.51**	0.34, 0.68	5.99	23.15*	35
High risk of bias (>1)a	15	0.53**	0.36, 0.70	6.01	22.24	37
Lowest risk of bias (0)b	11	0.59**	0.39, 0.80	5.73	18.64*	46
Blinded RCTs onlye
All eligible CBTp RCTs	24	0.36**	0.20, 0.51	4.48	49.10**	53
Case formulation only	19	0.43**	0.26, 0.61	4.95	39.17**	54
Case formulation + primary outcomec,d	14	0.55**	0.37, 0.73	5.99	21.36	39
Additional analyses
Group CBTp	4	0.11	−0.18, 0.41	0.76	3.15	5
Hallucinations as secondary outcome	5	0.05	−0.15, 0.24	0.46	3.87	0
Virtual-reality CBTp	2	0.56**	0.22, 0.89	3.27	0.75	0
Self-help CBTp	3	0.47	−0.42, 1.37	1.03	9.26**	78
After removal of 2 outliers
Any risk of bias score included	26	0.27**	0.15, 0.40	4.37	34.35	27
High risk of bias (>1)a	24	0.27**	0.14, 0.39	4.16	32.52	29
Lowest risk of bias (0)b	16	0.31**	0.16, 0.46	4.05	24.21	39
Case formulation only	19	0.32**	0.19, 0.45	4.91	23.01	22
Case formulation + primary outcomec,d	14	0.41**	0.29, 0.54	6.56	9.64	0
Case formulation, primary outcome + RoBa–c	9	0.44**	0.31, 0.58	6.46	6.11	0
Excluding RCTs with high ratio nonschizophrenia spectrum
Any risk of bias score included	26	0.32**	0.17, 0.47	4.23	49.46**	50
Lowest risk of bias (0)b	16	0.38**	0.19, 0.57	3.92	38.78**	61
Case formulation + primary outcomec,d	16	0.47**	0.30, 0.64	5.28	24.99	40
Case formulation, primary outcome + RoBa–c	10	0.58**	0.37, 0.79	5.35	17.58*	49

Note: All comparisons were using random model. Risk of bias scores refer to assessment using adapted version of the Cochrane Risk of Bias tool (0–4). CBTp, cognitive behavioral therapy for psychosis; CF, case formulation; CI, confidence interval; g, Hedges’s g; n/a, not applicable; RCT, randomized controlled trial; RoB, risk of bias; TAU, treatment-as-usual.

Sensitivity analysis exclusions were as follows:

^aRisk of bias score greater than 1 excluded: McLeod et al (2007); Peters et al (2010).

^bRisk of bias score greater than 0 excluded: Cather et al (2005); Durham et al (2003); Gottlieb et al (2017); Krakvik et al (2013); Leff et al (2013); McLeod et al (2007). Peters et al (2010); Trouwer et al (2004); Wykes et al (2005).

^cHallucinations as primary outcome only: Birchwood et al (2014); Garety et al (2008); Haddock et al (2009); Tarrier et al (2014); Trouwer et al (2004).

^dCase formulation only: Freeman et al (2015); Gottlieb et al (2017); Hazell et al (2017); McLeod et al (2007); Penn et al (2009); Wykes et al (2005).

^eNonblinded RCTs excluded: Krakvik et al (2013); McLeod et al (2007); Peters et al (2010).

*P < .05. **P < .01.