BETHESDA, MD (NIH) -- Impaired memory and motor skills were found in crack-cocaine users up to 6 months after their last use of the drug. Individuals with a history of heavy crack use had the most severe impairments. The researchers believe that these deficits are evidence of brain damage caused by substance abuse.

The NIDA-supported researchers administered a battery of comprehensive neuropsychological tests to 20 crack-dependent subjects, 37 crack-and-alcohol-dependent subjects, and 29 individuals with no history of drug or alcohol abuse. The tests were given twice-the first time following 6 weeks of abstinence from drugs and again after 6 months of drug abstinence. The tests assessed the subjects' attention span, decision-making, spatial processing, immediate and delayed memory, calculation ability, reaction time, verbal fluency, and psychomotor skills.

Both drug-abusing groups showed significant cognitive impairments at both the 6-week and the 6-month time points. The largest effects were found in the executive function and spatial processing assessments.

With approximately 2 million cocaine abusers in the United States, the finding that brain damage resulting in long-term impaired mental and physical functioning can result from its use makes developing and utilizing effective prevention and treatment methods an urgent public health priority.