The effects of meth are similar to cocaine but are much longer lasting, sometimes 8 to 24 hours. Meth causes a sense of energy, alertness, talkativeness, and well-being that users find pleasurable. At the same time, the user experiences signs of sympathetic nervous-system stimulation. When injected or smoked it causes an intense feeling of euphoria. With prolonged and high-dose use, the locomotion activity often becomes focused in repetitive movements like drawing repeated patterns.
Body temperature is raised.
The person may be feeling itchy all over and scratching. Psychologically, methamphetamine use can make the user feel increased alertness, a sense of well being, or paranoia. Other psychological effects are hallucinations, aggressive behavior, disturbed sleep, excitation, increased talking, panic, anxiousness, nervousness, delusions of grandeur, and severe depression. These neurotransmitters then leak out and interact with receptors. The rush that comes from smoked or injected meth is a result of a large release of dopamine which creates an extreme craving for another dose as soon as the effects wear off.