[willcannings]

People with depression do not generally have low serotonin levels, and it's unlikely low serotonin is the cause of chronic depression. If it was, serotonin agonists would be effective much faster than the 4-8 weeks they currently take. There's some evidence that increased serotonin levels modulate glutamate after about 4 weeks, and glutamate antagonists like Ketamine are effective on depression more rapidly than serotonin agonists (as quick as 40m in some studies).

Also the depression effect of alcohol is completely different to chronic depression, any mood effects you feel during a hangover are likely related to reduced dopamine.

Sleep is very important though, and, in Australia at least, melatonin is commonly prescribed for sleep issues that have a psychiatric cause.

[joesmo]

"Blood levels of serotonin are measurable -- and have been shown to be lower in people who suffer from depression – but researchers don't know if blood levels reflect the brain's level of serotonin.

"Also, researchers don't know whether the dip in serotonin causes the depression, or the depression causes serotonin levels to drop.

"Although it is widely believed that a serotonin deficiency plays a role in depression, there is no way to measure its levels in the living brain." -- (http://www.webmd.com/depression/features/serotonin)