Substance use disorder occurs when a person needs alcohol or another substance (drug) to function normally. Abruptly stopping the substance leads to withdrawal symptoms. Addiction means that a person has a strong urge to use the substance and cannot stop, even if they want to.
So it is important to maintain positive nitrogen balance in the body while sleeping. When you do and conditions are right so that your rate of protein synthesis exceeds your rate of degradation, and you maintain a positive nitrogen balance, you can grow while you sleep.
The sleep cycle repeats 4-6 times a night. We don't necessarily always progress through the sleep stages in a linear fashion. If your sleep is normal, you may reach your first REMcycle 60 to 90 minutes after you fall asleep, having gone from stage 1 to 2 to Delta to REM. This Delta may last 10 to 15 minutes and this REM may be very short.