As alcohol consumption increases or wears off, serotonin levels and the activity of mood circuits decrease, leading to a decline in mood.

“however the metabolic byproducts of alcohol like acety alahi disrupt this circuitry as drink continues this effect isn't sustainable serotonin levels and the activity of serotonergic neurons Begin to Fall this decreases why the initial positive effects of alcohol wear off after a few drinks”

“when you first drink alcohol these serotonergic neurons are stimulated to release more serotonin which contributes to the feel-good sensations often experienced in early drinking this is why those first few drinks can feel particularly rewarding and relaxing”