Amphetamines can pull people into a vicious cycle of addiction, but new research now shows that people who abuse these stimulants are also five times more likely to develop psychosis than non-users.
The effect of "speed" on neurotransmitter signaling in the brain often causes psychosis symptoms such as paranoia, voices and hallucinations. These typically resolve after a few days, but may persist for years in up to 15% of users.
While the link between amphetamine abuse and psychosis is known, the degree of psychosis risk or the effectiveness of drug rehabilitation therapy has been unclear.
To learn more, the researchers analyzed data on more than 74,600 illicit amphetamine users in Taiwan and a comparison group of more than 298,000 non-users matched for age and sex.
Compared with non-users, amphetamine users had higher rates of: depression (2% versus 0.4%); anxiety (0.9% versus 0.3%); ischemic heart disease (1.3% versus 0.8%); cardiovascular disease (0.8% versus 0.45%); and stroke (1.3% versus 0.7%).
By the end of 10 years of follow-up, speed users were far more likely to have psychosis than non-users. Rates were 468 per 100,000 people among speed users and 77 per 100,000 among non-users, according to the study published online Feb. 14 in the journal Evidence-Based Mental Health.
Among speed users, psychosis was more common among those 45 and older, and also among those with a longer arrest record. Those who had been arrested five or more times had a more than six times greater risk of psychosis, the researchers noted in a journal news release.
The study also found that speed users who went to drug rehab during deferred prosecution were 26% less likely to develop psychosis than those who didn't. This suggests that rehab may help lower the risk of psychosis, the study authors said.
"The relation of an induced paranoid psychosis with amphetamine abuse has been known for many decades. Nonetheless, our findings are from a detailed and comparative analysis using a comprehensive and large population dataset," according to Cynthia Wei-Sheng Lee, of the Centre for Drug Abuse and Addiction at China Medical University Hospital in Taiwan, and colleagues.
"Furthermore, it would be worthwhile to investigate the health benefits and cost effectiveness of deferred prosecution for drug crime offenders by providing appropriate therapy for drug addiction," the authors concluded.
The estimated worldwide rate of amphetamine use is less than 1%, but about one in 10 users become addicted.
There's more on amphetamines at the U.S. Drug Enforcement Administration.
SOURCE: Evidence-Based Mental Health, news release, Feb. 14, 2022