With prolonged high-dose use or long binges, stimulant psychosis may develop. The psychotic user may feel intensely paranoid, hear voices, and experience bizarre delusions, believing, for example, that other people are talking about him or following him. Methamphetamine-induced panic and psychosis can be extremely dangerous and may result in incidents of extreme violence.

It is not unusual for psychosis to persist for days after the last dose of methamphetamine. Indeed, there are many reports of users remaining paranoid, delusional, apathetic, and socially withdrawn for weeks. Occasionally, methamphetamine-related psychosis lasts for years. But, in these cases, experts believe the drug has probably triggered symptoms of a pre-existing mental disorder.