June 5 (HealthDay News) -- Teens with bipolar disorder are at greater risk of smoking and substance abuse, says a Massachusetts General Hospital (MGH) study that supports previous research.

"This work confirms that bipolar disorder in adolescents is a huge risk factor for smoking and substance abuse, as big a risk factor as juvenile delinquency," study leader Dr. Timothy Wilens, director of substance abuse services in MGH Pediatric Psychopharmacology, said in a prepared statement.

"It indicates both that young people with BPD (bipolar disorder) need to carefully be screened for smoking and for substance use and abuse and that adolescents known to abuse drugs and alcohol -- especially those who binge use -- should also be assessed for BPD," said Wilens, who is also an associate professor of psychiatry at Harvard Medical School.

He and his colleagues analyzed data on 105 teens with bipolar disorder who were enrolled in the study at an average age of 14 and followed into adulthood. The study also included a control group of 98 teens with no mood disorders.

Incidence of alcohol abuse or dependence, drug abuse or dependence, and smoking was significantly higher in the bipolar disorder group than in the control group. Overall, the rate of substance abuse was 34 percent in the bipolar disorder group compared to 4 percent in the control group.

The study also found that young people whose bipolar symptoms began in adolescence were more likely to abuse drugs and alcohol than those who started having bipolar symptoms in childhood.

"It could be that the onset of mood dysregulation in adolescence puts kids at even higher risk for poor judgment and self-medication of their symptoms," Wilens said. "It also could be that some genetic switch activated in adolescence turns on both BPD and substance abuse in these youngsters. That's something that we are currently investigating in genetic and neuro-imaging studies of this group."

Determining whether bipolar disorder begins before the start of substance abuse could prove of major importance.

"If BPD usually precedes substance abuse, there may be intervention points where we could reduce its influence on drug and alcohol abuse. Aggressive treatment of BPD could cut the risk of substance abuse, just as we have shown it does in ADHD," Wilens said.

The study was published in the June issue of the journal Drug and Alcohol Dependence.

SOURCE: Massachusetts General Hospital, news release, June 2, 2008