Massachusetts General Hospital (MGH) researchers have found that treatment with stimulant drugs does not increase and appears to significantly decrease the risk that girls with ADHD will begin smoking cigarettes or using alcohol or drugs. Their report in the October Archives of Pediatrics and Adolescent Medicine parallels the findings of several earlier studies in boys, which needed to be confirmed in girls.
"Girls with ADHD actually tend to get into trouble with substance abuse earlier than do boys with the disorder, so confirming those results was not simply academic," says Timothy Wilens, MD, director of the Substance Abuse Program in the MGH Pediatric Psychopharmacology Department, who led the study. "This is also one of the first naturalistic studies showing reduced risk of cigarette smoking in adolescents being treated for ADHD and is consistent with a 2006 prospective trial of ours that found that participants receiving stimulant treatment had less risk of smoking than those not receiving stimulants."
It is well known that individuals with ADHD have a significantly increased risk for cigarette smoking and substance abuse, and concerns that treatment with stimulant drugs may increase the risk of drug or alcohol abuse have often been expressed. Wilens and his MGH colleagues have conducted several studies in boys and young men with ADHD, the overall conclusions of which are that stimulant treatment decreases the risk and delays the onset of substance abuse in adolescence but neither increases nor reduces the risk of using tobacco, alcohol or drugs in adulthood. Evidence on treatment's impact for girls has been limited and conflicting, with at least one study suggesting the ADHD-associated risk may persist in spite of treatment.
Using data from a larger, long-term investigation of the impact of ADHD on the risk of substance abuse in girls, the researchers analyzed information from 114 participants with ADHD who had enrolled at the ages of 6 to 18. Standardized assessments for the use, abuse and dependence on tobacco, alcohol, marijuana or other drugs were conducted 5 years after initial study enrollment. Comparing results from the 94 participants who received stimulant treatment with the 20 who had not been treated indicated that treatment cut in half the risk of smoking, drinking alcohol or drug abuse. In participants who did develop substance abuse, whether or not they had received stimulant treatment had no effect on factors like when they began using substances and the level of dependence.
"Right now we can't say if the observed protective effect of stimulant treatment will continue into adulthood or disappear as it did in our studies in young men," Wilens explains. "But we suspect that the longer a girl is successfully treated for ADHD, the more likely she is to be at reduced risk for smoking and substance use or abuse. We can confidently say that stimulant treatment does not increase the risk of future substance abuse or smoking in girls with ADHD and at least delays the onset of cigarette smoking and substance abuse." Wilens is an associate professor of Psychiatry at Harvard Medical School.