Reference
Scientific research & studies on Yoga, meditation, and pranayama
Peer-reviewed research on yoga, meditation, and prāṇāyāma.
Yoga Practice Linked to Increased Brain GABA and Reduced Depressive Symptoms
Twelve weeks of Iyengar yoga plus coherent breathing, in people with major depressive disorder. Two groups: three sessions a week or two. Depression scores (BDI-II) improved significantly in both.
The more interesting finding is chemical. Thalamic GABA — a calming neurotransmitter — was measured by MRS. It rose significantly in the two-session group, with a trend in the full cohort, comparing before the program to right after the final practice. And the rise was short-lived: measured before that final session, the increase was there if the last practice was recent — within about four days — and gone at about eight.
Be clear about what this is. The authors call the support tentative: the study links yoga to a GABA rise and to improved mood; it does not prove one causes the other. What it does suggest is practical — the effect fades in days. If GABA is part of how this works, practice at least weekly. Regularity, not dosage, is what the data reward.
https://www.liebertpub.com/doi/10.1089/acm.2019.0234
Study: Streeter et al., "Thalamic Gamma-Aminobutyric Acid Level Changes in Major Depressive Disorder After a 12-Week Iyengar Yoga and Coherent Breathing Intervention," Journal of Alternative and Complementary Medicine 26, no. 3 (2020).