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Correction ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Psychol. | doi: 10.3389/fpsyg.2019.01868

Corrigendum: Mehl, S., Werner, D. & Lincoln, T. M. (2015). Does Cognitive Behavior Therapy for Psychosis (CBTp) show a sustainable effect on delusions? A meta-analysis. Frontiers in Psychology, 6: 1450. Doi: 10.3389/fpsyg.2015.01450.

 Stephanie Mehl1, 2*, Dirk Werner3 and  Tania M. Lincoln3
  • 1University of Marburg, Germany
  • 2Frankfurt University of Applied Sciences, Germany
  • 3Universität Hamburg, Germany

Text Corrections.

In the original article, there was a mistake in the **Abstract-section (page 1, line 16)**, the effect size of the comparison between CBTp and TAU after a follow-up period of 47 weeks was incorrect: “Meta-analytic integration resulted in a significant small to medium effect size for CBTp in comparison to TAU at end-of-therapy (k=13; d ̅= .27) and after an average follow-up period of 47 weeks (k = 12, d ̅= 0.25)”.
A correction in the **Abstract-section (page 1, line 16)** has been made and the effect size was corrected, as follows: **Meta-analytic integration resulted in a small to medium effect size for CBTp in comparison to TAU at end-of-therapy (k=13; d ̅= .27) and after an average follow-up period of 47 weeks (k = 12, d ̅= 0.16).**

In the original article in the **Abstract section (page 1, line 20-22)**,the discussion of the results was misleading (“The findings suggest that CBTp is superior to TAU and that this superiority is maintained over the follow-up period”).

A correction has been made in the **Abstract section (page 1, line 20-22)**, the sentence has been changed as follows: * The findings suggest that CBTp is superior to TAU post-therapy in bringing about a change in delusions. Nevertheless, this superiority is not maintained over the follow-up period.**

In the **results section, subsection “Descriptive information on included studies” (page 3, second column, paragraph 3)**, the description of studies was incorrect: “Only one of these studies did not use single-blind assessment (Foster et al., 2010) and only one study (Lincoln et al., 2012) used a self-reported measure (Peters et al. Delusions Inventory: Peters et al., 1999).”
A correction as been made in the **results section, subsection “Descriptive information on included studies” (page 3, second column, paragraph 3)** and the new description of studies is as follows: **Five of the studies did not use singe-blind assessment (Foster et al., 2010; Kråkvik et al., 2013; O' Connor et al., 2007; Tarrier et al., 1993; Waller et al., 2015) and only one study (Lincoln et al., 2012) used a self-report measure (Peters et al. Delusions Inventory: Peters et al. (1999).**

In the **results-section, subsection “Comparison of CBTp and Treatment as Usual (TAU)”, second column, second paragraph**, the mean effect size is incorrect: “The estimate for the mean effect size of CBTp compared to TAU was small to medium (d ̅=0.25, SE=0.09, p=0.006, CI: 0.07, 0.43). The between-study variance was τ ̂^2=0.03 (95%-CI: 0.00, 0.17), and the Q-statistic (Q=17.49, df=11, p=0.094) was non-significant. The value of I2=36.7% indicated a small to medium level of heterogeneity. The regression test for funnel plot assymetry revealed a statistically non-significant result (p=.80), thus, there was no indication of a bias.”

A correction has been made to the **results-section, subsection Comparison of CBTp and Treatment as Usual (TAU), second column, second paragraph**. The new section is as follows: ** The estimate for the mean effect size of CBTp compared to TAU was small and non-significant (d ̅=0.16, SE=0.10, p=0.098, CI: -0.03, 0.35). The between-study variance was τ ̂^2=0.04 (95%-CI: 0.00, 0.23), and the Q-statistic (Q=18.63, df=11, p=0.068) was non-significant. The value of I2=43.38% indicated a small to medium level of heterogeneity. The regression test for funnel plot assymetry revealed a statistically non-significant result (p=.15), thus, there was no indication of a bias.


In the **results-section, subsection “Comparison of CBTp and Treatment as Usual (TAU)”, second column, second paragraph**, the reports on exclusion of studies with patients who did not use medication or suicidal patients, is incorrect: “However, exclusion of these studies revealed comparable mean effect sizes (CBTp vs. TAU at end-of-treatment: d ̅ = 0.32; CBTp vs. TAU at follow-up: d ̅= 0.22.”
A has been made to the **results-section, subsection Comparison of CBTp and Treatment as Usual (TAU), second column, second paragraph**. The new section is as follows: **“However, exclusion of these studies revealed comparable mean effect sizes (CBTp vs. TAU at end-of-treatment: d ̅ = 0.32; CBTp vs. TAU at follow-up: d ̅=.12”**

In the **discussion section (page 10, first column, second paragraph)**, the results are presented incorrectly: “First, our results suggest that CBTp is more beneficial in changing delusions than standard treatment and that this effect does remain stable after an average follow-up period of more than half a year”.
A correction has been made to the **discussion section (page 10, first column, second paragraph)**, the presentation of the results is as follows: **First, our results suggest that CBTp is more beneficial in changing delusions than standard treatment. But, the effect of CBTp on delusions did not remain stable after an average follow-up period of 47 weeks. Interestingly, we performed an additional analysis that solely included studies that reported results at two time points: end-of-treatment and at follow-up. Results of this analysis suggest that CBTp was more effective than standard treatment over the follow-up period (k=11, d ̅=0.21, SE=0.10, p=0.035, CI: 0.01, 0.41). This suggests on the one hand, that present meta-analytic results of comparisons between CBTp and standard treatment at follow-up are still unstable as they are based on a still low number of studies. On the other hand, CBTp might be not effective in reducing delusions in the long term. Still, more RCTs that address the question of change in delusions and assess the stability of CBTp over a follow-up period are necessary to investigate this important question. **

In the **discussion section (page 11, fourth paragraph**, the description of the results is incorrect: “To sum up, our results suggest that CBTp is superior to TAU in regard to changing delusions and that this superiority is maintained over the course of the follow-up period”.
A correction has been made in the **discussion section (page 11, fourth paragraph**, the corrected paragraph is as follows: **To sum up, our results suggest that CBTp is superior to TAU in regard to changing delusions. Our preliminary results suggest that CBTp effects might not be maintained over the course of the follow-up period.**

Keywords: Meta-analysis, Delusions - psychology, psychosis, cognitive behavior therapy (CBT), effectiveness

Received: 29 Jun 2019; Accepted: 29 Jul 2019.

Edited by:

Francesco Pagnini, Catholic University of the Sacred Heart, Italy

Copyright: © 2019 Mehl, Werner and Lincoln. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Stephanie Mehl, University of Marburg, Marburg, Germany, stephanie.mehl@staff.uni-marburg.de