Specific withdrawal symptoms can wary depending on the substance a person was using, the amount the person was using, and how long they have been using that substance for. The more used to a drug a person’s body is, the worse the withdrawal symptoms will be. In very extreme case, withdrawal can lead to death.
In general, withdrawal symptoms tend to be the opposite of the effects of a drug. For example, if a drug helps you sleep, you will likely suffer from insomnia as you are going through withdrawal.
Withdrawal from Depressants:
Decreased appetite
Anxiety
Change in perception of light, sounds, smell, etc.
Weakness
Insomnia
Upset stomach
Hallucinations
Tremors
Convulsions
Delirium Withdrawal from Stimulants:
Increased appetite
Anxiety
Fatigue
Excessive sleep
Vivid dreams
Depression
Suicidal ideation