The most serious mental harm that has been shown to accompany amphetamine use is indeed dangerous and severe. Psychosis, depression, suicidal behavior, violence, delusions, hallucinations all can result from heavy amphetamine use. Common hallucinations can include feelings of paranoia, visual or tactile impressions. At one time in the research of effects of amphetamines, it was thought that all these symptoms were just brought out in a susceptible person by the amphetamine use. It has since been proven that heavy amphetamine use can cause these problems in a mentally healthy and stable person.