Study: Impaired motor skills can linger in drug users

Recreational drugs like “MDMA” and amphetamines have long been linked to a variety of movement disorders, and a new study suggests that basic motor-skill impairment may linger even among former users.

For the study, researchers tested how well current and former amphetamine users could hold their arms in a variety of positions, an indicator of basic motor skills, and compared their abilities to people who had never used these drugs. Both drooping arms and tremors were more common in current stimulant users than in people who never used the drugs. Former users also had more tremors than nonusers.

“Holding your arms out for one minute should not be seen as difficult — yet regular stimulants users showed significant deficits in this very simple and basic human skill,” said senior study author Andrew Parrott of Swansea University in the UK.

Stimulants work by increasing dopamine levels in the brain. While tremors are a side effect associated with stimulants, this side effect is less likely with lower doses and short-term use.

Recreational users may take much bigger doses of stimulants like cocaine or ecstasy or MDMA that increase dopamine levels too much and permanently damage neurons in the brain, said Jason White, head of the School of Pharmacy and Medical Sciences at the University of South Australia.

For the study, researchers tested motor skills of 20 currentz stimulant users, 20 former users and 20 people who had never tried the drugs recreationally.