Stimulants are both diverted from legitimate channels and clandestinely manufactured exclusively for the illicit market. They are taken orally, sniffed, smoked and injected. Abuse is often associated with a pattern of being use, that is, consuming large doses of stimulants sporadically. Heavy users may inject themselves every few hours, continuing until they have depleted their drug supply or reached a point of delirium, psychosis and physical exhaustion. During this period of heavy use, all other interests become secondary to recreating the initial euphoric rush.
Tolerance can develop rapidly, and both physical and psychological dependence occur.
Therapeutic levels of stimulants can produce exhilaration, extended wakefulness and loss of appetite. These effects are greatly intensified when large doses of stimulants are taken. Psychological effects include agitation, hostility, panic, aggression and suicidal or homicidal tendencies. Paranoia, sometimes accompanied by both auditory and visual hallucinations, may also occur. In overdose, unless there is medical intervention, high fever, convulsions and cardiovascular collapse may precede death.