The same exact dose of Methadone could be ineffective for one person, but could also cause a deadly overdose for someone else who isn't tolerant to that dose.
The brains of Ecstasy users who experience serotonin depletion because of their Ecstasy will take a significant amount of time to restore the level of serotonin needed to perform important physiological and psychological functions.
The crack high typically wears off within 5 to10 minutes, causing users to feel 'down' or depressed, more than before taking the drug.
Rare but occasional heroin withdrawal symptoms which can occur when someone abruptly stops using the drug are cardiac arrhythmias, strokes, seizures, dehydration and suicide attempts.