GABA is the brain's main calming chemical, and the receptors it acts on — called GABAA receptors — are targets for many existing medications like sedatives and anti-anxiety drugs. This review examines how these receptors are involved in several mental health conditions, including PMDD, postpartum depression, major depression, and schizophrenia, and what new treatments are being developed.
For PMDD specifically, the review explains that certain types of GABAA receptors in the brain change their levels across the menstrual cycle. During the phase when progesterone is falling (the late luteal phase), these receptor changes — combined with shifting levels of natural brain steroids called neurosteroids — may contribute to the anxiety, irritability, and low mood that characterize PMDD. Interestingly, there is no consistent evidence that women with PMDD have different neurosteroid levels compared to those without PMDD. Instead, the problem may be in how the brain responds to normal hormonal shifts. Women with PMDD also appear more sensitive to stress during this phase.
One promising treatment approach highlighted is sepranolone, a drug that blocks the action of neurosteroids at GABAA receptors. In a randomized, placebo-controlled clinical trial, sepranolone given during the luteal phase reduced PMDD symptoms and negative mood. The review emphasizes that more research is needed to fully understand how GABAA receptor changes and neurosteroid levels interact across the menstrual cycle before more targeted PMDD treatments can be developed.
The review also discusses the success of neurosteroid-based treatments for postpartum depression (brexanolone and zuranolone), which share some biological overlap with PMDD. A table of over a dozen new drugs targeting specific GABAA receptor subtypes currently in development highlights that this is an active and evolving area of research.
Key findings
- Brexanolone (IV allopregnanolone) was FDA-approved for postpartum depression in 2019 and zuranolone (oral neuroactive steroid) was FDA-approved for postpartum depression in 2023, both acting as GABAA receptor positive allosteric modulators
- A randomized placebo-controlled trial showed that the neurosteroid antagonist sepranolone reduced self-reported symptoms and negative mood in women with PMDD when administered during the luteal phase
- Nonselective GABAA PAMs such as benzodiazepines and barbiturates have largely failed to show antidepressant efficacy in major depressive disorder, with any benefits potentially reflecting improved sleep and reduced anxiety rather than core symptom improvement
- Preclinical studies found that hippocampal GABAA receptor δ and γ subunit expression changes across the estrous cycle, with δ subunits elevated during diestrus and increased tonic inhibition in the dentate gyrus, suggesting dysregulation could contribute to PMDD
- α5 subunit-selective negative allosteric modulators (NAMs) restored normal reward behaviors within 24 hours in chronically stressed rats and sustained benefits for up to 7 days, without the side effects associated with ketamine
- No consistent evidence currently supports the idea that differences in endogenous neurosteroid levels are associated with PMDD occurrence in women, though women with PMDD show altered sensitivity to GABAA receptor-modulating neuroactive steroids
Methods, briefly
Narrative review of preclinical and clinical literature on GABAA receptor pharmacology and its relevance to neuropsychiatric disorders. Covers molecular pharmacology, receptor subunit heterogeneity, binding sites, and clinical trial results for various PAMs and NAMs. No original data collection; synthesizes published studies including randomized controlled trials, preclinical animal models, neuroimaging, and genetic studies.
Limitations to keep in mind
- Narrative review without systematic search methodology, introducing potential selection bias in cited literature
- Author has competing interests as inventor on patents for α5-selective NAMs for psychiatric use
- Much of the mechanistic evidence comes from preclinical rodent models that may not fully translate to human PMDD or depression
- Clinical trial data for several novel compounds (e.g., basmisanil, TPA023) showed negative or inconsistent results in humans despite promising preclinical profiles
- Human brain GABAA receptor subunit distribution data are incomplete compared to rodent data
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