Teens with attention-deficit/hyperactivity disorder (ADHD) - the most common childhood psychiatric condition in the United States - are less likely to finish high school on time than students with other mental-health disorders that often are considered more serious, a large national study by researchers at the UC Davis School of Medicine has found. The study found that nearly one third of students with ADHD, twice the proportion as students with no psychiatric disorder, either drop out or delay high school graduation.
The study also examined the effects of substance use and abuse on high school graduation and found that among students who engage in substance use, including alcohol and other drugs, teens who smoke cigarettes are at greatest risk of dropping out.
There are three types of ADHD: the hyperactive type, the inattentive type and the combined type. Symptoms include not being able to pay attention, daydreaming, being easily distracted and being in constant motion or unable to remain seated.
"Most people think that the student who is acting out, who is lying and stealing, is most likely to drop out of school. But we found that students with the combined type of ADHD - the most common type - have a higher likelihood of dropping out than students with disciplinary problems," said Julie Schweitzer, an expert on ADHD at the UC Davis MIND Institute, an associate professor of psychiatry and behavioral sciences and the study's senior author. "This study shows that ADHD is a serious disorder that affects a child's ability to be successful in school and subsequently in a way that can limit success in life."
Published online in July in the Journal of Psychiatric Research, the study "Childhood and Adolescent-onset Psychiatric Disorders, Substance Use, and Failure to Graduate High School on Time" found that 32.3 percent of students with the combined type of ADHD - which incorporates hyperactive and inattentive symptoms - drop out of high school. Fifteen percent of teens with no psychiatric disorder drop out.
"Understanding the factors that contribute to dropping out of high school has major public-health implications, given that a third of youth in this country do not complete high school on time. Supporting mental-health interventions for students may have a significant impact on reducing high school dropout," said study author Elizabeth Miller, an assistant professor of pediatrics and an adolescent medicine specialist at UC Davis Children's Hospital.
In 2006 an estimated 4.5 million children in the United States between 5 and 17 years of age were diagnosed with attention-deficit/hyperactivity disorder, according to the Centers for Disease Control and Prevention. An estimated 9.5 percent of boys and 5.9 percent of girls are diagnosed with the condition.
The next most at-risk teens are students with conduct disorder, whose symptoms include aggression, lying, stealing, truancy, vandalism and a general pattern of rule-breaking. Thirty-one percent of students with conduct disorder drop out, said Joshua Breslau, associate professor of internal medicine and the study's lead author. Breslau said the research shows there are different pathways to poor high school performance.
"This study identifies multiple ways in which mental-health problems can affect education at the high school level. Attention-deficit/hyperactivity disorder impacts achievement because it affects how well students are able to perform basic classroom tasks from paying attention to turning in their homework," said Breslau. "Students with conduct disorder are able to do just as well as everyone else academically but disciplinary issues and dealing with the routines of school life may cause them to drop out."
For the study, the researchers examined the joint, predictive effects of childhood- and adolescent-onset psychiatric and substance-use disorders on failure to graduate high school on time, using data collected during 2001 and 2002 from the National Epidemiological Survey of Alcohol and Related Conditions. A total of approximately 43,000 racially diverse male and female participants over 18 from throughout the United States were interviewed by U.S. Census Bureau representatives about the age of onset of psychiatric diagnoses, substance use and high school graduation. Respondents were excluded if they had less than eight years of education or arrived in the U.S. after age 13. A total of 29,662 of the respondents were included in the UC Davis study.