Correcting and interpreting the effect of cognitive therapy versus exposure in anxiety disorders
1 Department of Clinical Epidemiology and Biostatistics, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada
2 Department of Adult Education and Counselling Psychology, University of Toronto, Toronto, Canada
BMC Psychiatry 2012, 12:202 doi:10.1186/1471-244X-12-202Published: 20 November 2012
Dr. Ougrin’s evaluation of cognitive therapy versus exposure in anxiety disorders reported a standardised mean difference [SMD] (95% confidence interval [CI]) of 0.52 (0.37, 0.74) for short-term outcomes and 0.46 (0.29, 0.73) for long-term outcomes in social phobia, and 0.88 (0.69, 1.11) for short-term outcomes and 1.05 (0.80, 1.37) for long-term outcomes in posttraumatic stress disorder (PTSD). These were incorrectly meta-analysed. Upon re-analysis, we found that the correct SMD (95% CI) was −0.66 (−1.19, -0.14) for short-term outcomes and mean difference (95% CI) of −29.66 (−46.13, -13.19) on the Social Phobia subscale from the Social Phobia Anxiety Inventory for long-term outcomes in Social Phobia. For PTSD, the SMD (95% CI) for short-term outcomes was −0.13 (−0.36, 0.11) and 0.05 (−0.22, 0.32) for long-term outcomes. However, correcting the errors did not change the interpretation of the findings considerably.