A six-year study on 51 Vietnam veterans who were drug abusers of either mainly stimulants (11 people), mainly opiates (26 people), or mainly benzodiazepines (14 people) was carried out to assess psychiatric symptoms related to the specific drugs of abuse.
In January 2007, Belgian cyclist Johan Museeuw admitted that he took stimulants during the last years of his cycling career, and that he confided this earlier to Dedecker.
Amphetamine and other stimulants can create psychotic episodes which may be defined as bursts of dream activity erupting spontaneously into waking states, this is not due to the substance itself but rather a result of the prolonged suppression of cholinergic activity and REM sleep due to amphetamine or stimulant abuse.
Tryptophan and 5-hydroxy-tryptophan, for instance, can be used to help the body replenish serotonin levels in the brain after the use of MDMA, and vitamin supplements are appropriate for users of stimulants such as amphetamine.