Various causes have been proposed to explain the causes of<unk> .<unk>  binds to<unk> c receptors in the brain that, in turn, cause an increase in dopamine. Dopamine is the major chemical that stimulates reward centers in the brain. The brain recruits an opposing force to dampen the effects of<unk>  and this causes tolerance (the reduction in the effect of<unk> . The onset of this opposing force and the fact that the brain becomes used to and dependent on<unk>  to function normally is known as physical dependence. When<unk>  intake is decreased, the brain's opposing force is now unopposed and this causes withdrawal symptoms. It also appears that opiate, serotonergic, glutamic, cannabinoid, and corticotrophin receptors may play a role in<unk> . In addition, smoking becomes conditioned to environmental cues that can then prompt withdrawal symptoms. In the brain, the dorsal striatum may be associated with physical (motor) but not affective withdrawal sign.
Nicotine withdrawal
Drug withdrawal
Opioid withdrawal
Benzodiazepine withdrawal syndrome
Alcohol withdrawal syndrome
Post-acute-withdrawal syndrome
Alcohol intoxication
Antidepressant discontinuation syndrome