Depending on how much MDMA you took, you may end up depleting so much of your serotonin that fewer receptors are activated than before you took ecstasy, when you were in a normal brain state. This is what causes the "ate up" feeling that a lot of users experience when they come down. You can become very depressed at this point, feeling extremely non-social, tired and irritable.

Some people at this point are tempted to take more Ecstasy, because the contrast between how they were feeling an hour earlier and how they feel now is so extreme. But when they take more, it doesn't work. While it may give the user a little more energy (i.e increase the speediness), they won't recapture the empathy and other desirable MDMA effects. Remember, Ecstasy releases (and then depletes) the serotonin that you already have. It doesn't cause more serotonin to be created.

Your brain needs time in order to rebuild its serotonin levels. This could take up to two weeks. As expected, the larger the dose the greater the serotonin depletion and the longer it takes for your brain to replenish it.

Can these lowered serotonin levels cause depression? Yes. There are a few pharmacological reasons why MDMA use can lead to temporary yet prolonged periods of depression. Perpetually low serotonin levels resulting from weekly MDMA use is one of these reasons. If you take ecstasy on a regular basis, you may be releasing and depleting your serotonin before it has a chance to fully replenish itself. This means you will be operating on lower-than-normal serotonin levels most of the time, and this can lead to depression. Another reason you can get depressed has to do with "receptor downgrading," which we will be discussing soon.

How does your brain make serotonin in the first place, and why does it take so long for it to replenish its stores after they have been depleted by MDMA? Let's take a look . . .