Therapy by the Numbers
What a new meta-analysis reveals about the effectiveness of psychotherapy
In Case You Missed It…
Does psychotherapy work? A new meta-analysis by Mathias Harrer and colleagues concludes that it does, but more so for some disorders than others. Below are the Hedges’ g values for the 12 disorders covered by the meta-analysis. Hedges’ g is an effect size estimate similar to Cohen’s d. According to a convention in psychology:
0.2 = small
0.5 = medium
0.8 = large
Large Effects
Phobias: g = 1.25
Posttraumatic stress disorder: g = 1.18
Obsessive–compulsive disorder: g = 1.18
Social anxiety: g = 0.95
Generalized anxiety: g = 0.86
Panic disorder: g = 0.83
Problem gambling: g = 0.80
Depression: g = 0.73
Small-to-Moderate Effects
Prolonged grief: g = 0.49
Borderline personality disorder: g = 0.46
Suicidal ideation: g = 0.34
Psychotic disorders: g = 0.32
Here’s the main figure from the paper, with the fine-grained details for stats fans.
Takeaways
Psychotherapy works best for anxiety disorders, including phobias and OCD.
Even serious conditions like psychosis see some benefits, although the effects are notably smaller.
Cognitive behavioral therapy (CBT) is no more effective than other forms of therapy.
Psychotherapy is no less effective in non-Western nations than in Western ones, and no less effective in low- and middle-income nations than in wealthy ones.
One of the reasons I decided not to become a clinical psychologist was that I worried that therapy only really works for relatively mild disorders. It looks like I wasn’t completely off base - simple phobias, for instance, are much more easily treated than full-blown psychotic disorders. But I am pleased to see that the effect sizes aren’t negligible even for some of the most serious psychiatric conditions.
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Coming Soon to The Nature-Nurture-Nietzsche Newsletter…
Beyond g: The Genetics of Specific Cognitive Abilities
12 Things Everyone Should Know About the Dark Triad
The Problem of Free Will, Part 3: Does Determinism Make Us Bad?
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This is the third post in my “12 Things Everyone Should Know” series. You can find the full collection here.
Very cool. I have been a therapy skeptic and am happy to be proven wrong. Anecdotally, it does seem however, that a good fraction of patients don’t have a specific condition that they’re trying to address, as opposed to some miscellaneous personal problems. I wonder what therapy does for them.
Very cool you considered being a clinical psychologist but ended up doing something different that’s helping millions of people in a different way. I also started out on a psych path but ended up pivoting to audiology and eventually a resilience instructor in the military. The psych foundation has stayed with me though and influences everything I do.
Great stuff as always