 In accordance, acute administration of low doses of micronized progesterone (which reliably elevates allopregnanolone levels) has been found to have negative effects on mood, while higher doses have a neutral effect.The mechanism by which neurosteroid GABAA receptor PAMs like brexanolone have antidepressant effects is unknown.Other GABAA receptor PAMs, such as benzodiazepines, are not known to have antidepressant effects.