Fluoxetine's effect on neurosteroids is primarily related to an increase in allopregnanolone, a potent GABAA receptor positive allosteric modulator;[64] a reduction in circulating brain (primarily mesocorticolimbic) allopregnanolone has been associated with both depression and anxiety disorders.[64] Improvement in depressive symptoms in medicated individuals is correlated with fluoxetine-induced increases in allopregnanolone levels.[64] Norfluoxetine, a primary active metabolite of fluoxetine, produces a similar effect on allopregnanolone levels in the brain, and has therefore also been characterized as a selective brain steroidogenic stimulant.[64]