Not true. It is more important to go to bed at the same time and wake up at the same time everyday. Not everyone needs eight hours. In fact, if I get eight hours sleep I usually feel tired and groggy for the entire day.
Many drugs affect the release, arrest and efficacy of serotonin, including antidepressants, psychedelic hallucinogens, synthetic opiates, dissociatives, drugs for treating migraines, antihistamines, and stimulants such as MDMA.
Yes, there can be some important drug interactions with melatonin; melatonin is structurally similar to serotonin. Melatonin may have a more significant drug interaction with these medications, possibly increasing the blood levels of melatonin or causing other side effects: