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.
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.
Follow me on Twitter/X for more psychology, evolution, and science.
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?
How You Can Support the Newsletter
If you like what I’m doing with The Nature-Nurture-Nietzsche Newsletter, and want to support my work, there are several ways you can do it.
Like and Restack: Click the buttons at the top or bottom of the page to boost the post’s visibility on Substack.
Share: Send the post to friends or share it on social media.
Upgrade to Paid: A paid subscription gets you:
If you could do any of the above, I’d be hugely grateful. The support of readers like you helps keep this newsletter going and growing.
Thanks!
Steve
Related Reading From the Archive
12 Things Everyone Should Know About Mental Illness
This is the third post in my “12 Things Everyone Should Know” series. You can find the full collection here.
Interesting article, thank you. There is increasingly good evidence for Mentalization Based Therapy (MBT) for people with a diagnosis of BPD. This provides group MBT sessions alongside individual sessions.