5.03 Stimulants (Types, Intoxication, and Withdrawal) Psychiatry review for the USMLE Step 1 Exam. Stimulants increase CNS activity and activate the sympathetic nervous system. They can block reuptake of neurotransmitters or stimulate their release. Intoxication symptoms include agitation, dilated pupils, sweating, euphoria, hallucinations, and increased norepinephrine, epinephrine, dopamine, and serotonin levels. Prescribed stimulants: amphetamine, dextroamphetamine, and methylphenidate (used for ADHD). Recreational stimulants: methamphetamine, cocaine, MDMA, nicotine, and caffeine. Cocaine blocks reuptake of norepinephrine, epinephrine, and dopamine, and can cause hallucinations, paranoia, chest pain, and potentially cardiac death. Methamphetamine can cause tactile hallucinations where patients feel like bugs are crawling on their skin. MDMA can induce feelings of connectedness, heightened emotions, and hallucinations. Withdrawal from stimulants, particularly cocaine and methamphetamine, is characterized by depression, headache, malaise, fatigue, hypersomnolence, anhedonia, constricted pupils, vivid dreams, and flu-like symptoms. Withdrawal symptoms are opposite to the effects experienced during intoxication.