The Science
Yoga, GABA, and How Fast It Fades
Twelve weeks of yoga and slow breathing raised thalamic GABA in people with major depression. The rise may be short-lived — a trend, not a finding, and an argument for practicing weekly.
Twelve weeks of Iyengar yoga and coherent breathing at five breaths a minute, in people who met criteria for major depression. Thirty-two randomized to one of two doses — three ninety-minute sessions a week plus four homework sessions, or two plus three. Twenty-eight finished the scanning. Depression scores improved in both groups.
The chemistry is the interesting part. Thalamic GABA rose significantly in the lower-dose group, with a trend across everyone, comparing the first scan to a scan taken right after a final session.
Then the part people quote, which needs handling carefully.
The researchers looked at a scan taken after twelve weeks but before that final session, and split the group afterwards by whether GABA had gone up. The ones whose GABA was up had last practiced a mean of 3.9 days earlier. The ones whose GABA was not up had last practiced 7.8 days earlier.
Be clear about the whole study. There was no control group; the comparison is two doses of the same thing, not against nothing. The design cannot separate the postures from the breathing, because the intervention is a bundle. The sample is small. No blinded clinician rated the depression. The authors call their own support tentative — the study links yoga to a GABA rise and to better mood, and does not show one causes the other.
Whatever else it shows, it does not show that this banks. If GABA is part of how it works, the effect goes in days.
Which the tradition has always said, without the spectroscopy. Practice weekly at minimum. And note which group's chemistry actually moved: the one doing less.