Effect size of the efficacy of CBT

A meta-analysis included 41 randomized controlled trials that compared CBT with placebo.¹ In 34 of these studies, the intervention was delivered on an individual basis, whereas in the remaining 7 studies CBT was delivered to groups.¹

This meta-analysis of randomised placebo-controlled trials of CBT found:

• Moderate placebo-controlled effects of CBT on target disorder symptoms (Hedges’ g: 0.56)
• Small-to-moderate effects on other symptoms:
  • Other anxiety symptoms (Hedges’ g: 0.38), Depression (Hedges’ g: 0.31), Quality of life (Hedges’ g: 0.30)
• People receiving CBT experienced better response rates compared with placebo (OR: 2.97)

There was a mean of 11 CBT sessions across the studies.¹

Overall, there was an almost threefold higher response rate with CBT vs placebo.¹

ASD=acute stress disorder; CI=confidence interval; CBT=cognitive–behavioural therapy; GAD=generalized anxiety disorder; OCD=obsessive–compulsive disorder; OR=odds ratio; PD=panic disorder; PTSD=posttraumatic stress disorder; QoL=quality of life; SAD=social anxiety disorder