January 22, 2010 — Girls with attention-deficit/hyperactivity disorder (ADHD) are at high risk for psychiatric complications in young adulthood, particularly antisocial, addictive, mood, anxiety, and eating disorders, according to a longitudinal case-control study with follow-up of 11 years.
Published online in the January 15 issue of the American Journal of Psychiatry, investigators found that the risk for 6 composite lifetime diagnostic categories was significantly higher in girls with ADHD compared with controls, with hazard ratios of 6.8 for mood disorders, 2.1 for anxiety disorders, 7.2 for antisocial disorders, 3.2 for developmental disorders, 2.7 for substance dependence disorders, and 3.5 for eating disorders.
Girls with ADHD also had significantly higher 1-year prevalence of composite mood, anxiety, antisocial, and substance dependence disorders relative to the comparison group, investigators add.
"We were not surprised for these findings at all, but the overwhelming amount of research in ADHD is in boys, and we needed to extend our research to females as there are very few studies assessing what happens to girls with ADHD," Joseph Biederman, MD, Harvard Medical School, Boston, Massachusetts, told Medscape Psychiatry.
"So even though the findings are not different from boys with ADHD, it is very important to establish that girls are at very high risk of developing the same complications as boys," he added.
Original Sample
For the study, investigators analyzed data on 96 girls with ADHD and 91 comparison girls from the original longitudinal sample. All girls had completed a full follow-up assessment at a mean of 11 years after enrollment.
At the 11-year follow-up reassessment, 93% of girls with ADHD had received some form of treatment for the disorder — 1% counseling alone, 21% medication alone, and 71% counseling and medication.
During the year preceding the 11-year follow-up assessment, 42% of ADHD girls were also receiving some form of treatment, whereas the rate of full or subthreshold ADHD during the interval between year 5 and year 11 was 69%. The rate of current full or subthreshold ADHD was 62%.
Girls with ADHD had a significantly higher lifetime prevalence of major depression, bipolar disorder, separation anxiety disorder, agoraphobia, social phobia, specific phobia, panic disorder, generalized anxiety disorder, oppositional defiant disorder, conduct disorder, antisocial personality disorder, Tourette or tic disorders, language disorder, enuresis, and bulimia than comparison girls.
The 1-year prevalence of eating disorders did not differ significantly between the 2 groups, but mood, anxiety, and antisocial disorders all remained significantly higher in girls with ADHD after controlling for baseline psychopathology.
Table. Adjusted 1-Year Prevalence Estimates for Psychiatric Disorders in ADHD and Comparison Subjects at 11 Years of Follow-up
| Disorder | Comparison Group (95% CI) (n = 91) | ADHD Group (95% CI) (n = 96) |
| Mood disorders | 0.07 (0.03 – 0.14) | 0.23 (0.15 – 0.32) |
| Anxiety disorders | 0.21 (0.14 – 0.31) | 0.47 (0.37 – 0.57) |
| Antisocial disorders | 0.04 (0.02 – 0.11) | 0.21 (0.14 – 0.31) |
| Substance dependence disorders | 0.07 (0.04 – 0.15) | 0.31 (0.22 – 0.41) |
| Eating disorders | 0.03 (0.01 – 0.10) | 0.07 (0.03 – 0.14) |
ADHD = attention-deficit/hyperactivity disorder; CI = confidence interval
Multiple Factors at Play
There may be multiple reasons girls with ADHD are so highly predisposed to developing psychiatric complications in young adulthood, said Dr. Biederman. The risk factors that produce ADHD may also lead to a wide range of complications as girls mature, he said.
"Patients with ADHD are more impulsive and reactive and more prone to experiment with drugs and then transition from experimentation to abuse and then dependence," said Dr. Biederman.
Moreover, children with ADHD typically do not do well in school, at play or even within the family, all of which may serve to demoralize and upset them, setting the stage for depression and other psychiatric disorders in later life.
Whatever the various reasons or combinations of causes, "the comorbid conditions that girls with ADHD develop in themselves are very morbid and risky, and knowing that ADHD is associated with bad outcomes may allow clinicians to very aggressively diagnose and treat it and which may have important implications for diminishing the risk of comorbidity," said Dr. Biederman.
Strength of the Study
Scott Kollins, PhD, MS, Duke University School of Medicine, Durham, North Carolina, told Medscape Psychiatry that the strength of the longitudinal study is in showing that ADHD outcomes are just as poor for girls as they are for boys and that it is "really valuable" to demonstrate this kind of impairment into adulthood.
He also agrees with investigators that girls with ADHD are less likely to be referred for diagnosis and treatment in childhood and therefore are not receiving treatment for ADHD, the result of which is a possible future "pernicious course" as shown in this study. Dr. Kollins feels that the protective effect of early treatment of ADHD against poor outcomes later in life continues to be debated.
Nevertheless, "what is clear is that if you treat the impairment in ADHD, it’s a good thing and even if you do not have a huge impact down the road, if you intervene early, there is a possibility of reducing the risk for some of these other complications later on."
Dr. Biederman has received research support, consultation fees, or speaker’s fees from Abbott, Aiza, AstraZeneca, Bristol Myers Squibb, Celltech, Cephalon, Eli Lilly, Esai, Forest, GlaxoSmithKline, Gliatech, Janssen Pharmaceuticals, McNeil, Merck, NARSAD, National Institute on Drug Abuse, National Institute of Child Health and Human Development, National Institute of Mental Health, New River, Novartis, Noven, Neurosearch, Organon, Otsuka, Pfizer, Pharmacia, Prechter Foundation, shire, Stanley Foundations, UCB Pharma, and Wyeth. Dr Kollins has disclosed no relevant financial relationships.
Am J Psychiatry. Published online January 15, 2010.
