ADHD in Girls
David Rabiner, Ph.D., Durham, N.C.
One of the important shortcomings of most of the research based information on ADHD is that the vast majority of studies have been conducted solely on boys, or, have included very few girls in the sample. As a result, the scientific literature on ADHD is almost exclusively based on male subjects. Recently, a study funded by the National Institute of Mental Health on a large group of girls both with and without ADHD was published in the Journal of the American Academy of Child and Adolescent Psychiatry (Biederman, J. et al., (1999). Clinical correlates of ADHD in females: Findings from a large group of girls ascertained from pediatric and psychiatric referral sources. Journal of the American Academy of Child and Adolescent Psychiatry, 38, 966-975. In this study, the authors examined the clinical correlates of ADHD in girls so that similarities and differences with what has been found among boys with ADHD could be ascertained. This study represents the largest and most comprehensive study of girls with ADHD that has been published to date.
Participants in this study were girls between the ages of 6 and 18. There were 140 girls who had been diagnosed with ADHD based on structured psychiatric interviews conducted with the child's parent(s). In addition, 122 girls of similar ages and other backgrounds who did not have ADHD were included as comparison subjects. These two groups of girls were compared on a wide variety of characteristics so that the researchers could learn about the problems associated with ADHD in females specifically. The major findings are summarized below.
- Among the girls who were diagnosed with ADHD, 59% had the combined type (i.e. both inattentive and hyperactive/impulsive symptoms), 27% had the Predominantly Inattentive type, and only 7% had the Predominantly Hyperactive/Impulsive type.
- Overall, a significantly greater proportion of symptoms of inattention were present according to parents relative to either hyperactive/impulsive symptoms.
- Girls with ADHD were significantly more likely to be diagnosed with other disorders as well.
- Compared to girls without ADHD, girls with ADHD were more likely to be diagnosed with co-morbid conduct disorder, oppositional defiant disorder, mood disorders, anxiety disorders, and substance use disorders. Tic disorders and enuresis (i.e. bed wetting or day-time wetting) were also more common in the girls with ADHD.
- Overall, 45% of the girls with ADHD were diagnosed with at least one other condition. Only 4% of the girls with ADHD had more than two co-morbid disorders, however.
- Although the rate of co-morbid behavior disorders in girls with ADHD was high, it was still no more than half of the rate that has been previously reported for boys. Because disruptive behavior disorders are one of the main reason that children get identified and referred for treatment, the authors speculate that the lower incidence of these problems in girls with ADHD may partially explain the marked gender differences that are often found in children with ADHD who are receiving clinical treatment.
- The rate of mood and anxiety disorders in girls with ADHD was quite similar to what has been previously found in boys. Contrary to what some have suggested, there was thus no evidence in this sample of children that girls with ADHD are more likely than boys to have problems in these areas. There was, however, an indication that problems with substance use were more common among girls with ADHD than has been previously found to be true for boys. For example, girls with ADHD were about four times as likely to be smokers.
Cognitive, School and Family Functioning
Girls with ADHD had scores on measures of intellectual functioning and academic achievement that were modestly lower than what was found in the non-ADHD girls. They were also about 2.5 more likely to be diagnosed with a learning disability, more than sixteen times more likely to have repeated a grade in school, and almost ten times as likely to have been placed in a special class at school.
It is perplexing why girls with ADHD were so much more likely to have repeated a grade given that the difference in the academic achievement test scores were, although lower, not so dramatically different from other girls. I think this may reflect that fact that achievement testing - which is done on an individual basis-tends to reflect the highest level of work that children are capable of. In many instances, this is quite a bit higher than the level that a child with ADHD actually performs at on a day to day basis. So, these data may reflect the debilitating effect that ADHD has on a child's typical school performance, which can result in grade retention and special class placement even for children who are quite bright and capable.
Whatever the explanation, these data underscore how important it is for parents to insure that their daughter's educational needs are being carefully and adequately addressed. Children with ADHD are often legally entitled to special educational services to help address the unique needs that they have. You can learn about the educational rights for children with ADHD by going here. The parents of girls with ADHD also described their family life as less cohesive and reported greater amounts of conflict with their daughters.
The results of this study make clear that ADHD in girls is as serious a condition and has a comparably large negative impact on children's functioning and adjustment as it does in boys. Overall, the correlates of ADHD in girls were remarkably similar to what is known to be true for boys. Among the few differences found were that girls were less likely to be diagnosed with a co-morbid behavior disorder than boys (i.e. oppositional defiant disorder or conduct disorder) and perhaps more likely to have problems related to substance use. Rates of mood and anxiety disorders, and impairment in academic functioning appeared to be quite comparable.
The lower rates of disruptive behavior problems, along with the preponderance of inattentive symptoms relative to hyperactive/impulsive symptoms, may partially explain why ADHD in girls may often not be recognized. Because rates of mood and anxiety disorders were similar to what has been found in boys, the authors speculate that in conjunction with the lower levels of disruptive behavior and hyperactive/impulsive symptoms, this may lead clinicians to diagnose girls with the former types of disorders rather than ADHD. In fact, in a study recently published in the journal Pediatrics it was reported that pediatricians were significantly more likely to diagnose boys with ADHD than girls, even when the problems described by parents were quite comparable.
The authors stress that clinicians need to be aware that, despite their lower rates of disruptive disorders, ADHD in girls is a serious condition associated with impairment in multiple areas of children's functioning. Thus, there is no reason to assume that the treatment of girls with ADHD should be any less aggressive or comprehensive than that of boys.
Parents need to be aware that their daughter with ADHD is at significantly increased risk for a variety of other conditions as discussed above. In fact, in this study, almost 50% of girls with ADHD had at least one other diagnosable disorder. It is thus essential that evaluations of girls for ADHD take a broad look at their emotional, behavioral, social, and academic functioning so that a comprehensive treatment plan addressing all areas of important difficulty can be developed and implemented. In particular, given the indication of possible increased risk of substance use in girls with ADHD, this may be an area that is especially important for parents to monitor.
Too often, in my opinion, even if ADHD in females is identified, necessary attention to areas of difficulty apart from core ADHD symptoms may not be targeted in a child's treatment, or may not be addressed in the most helpful way. This is especially likely to be the case when a primary care physician is the sole treatment provider, as physicians are typically less attentive to a child's overall emotional and behavioral functioning in their evaluations, and may tend to rely on medication treatment alone when other interventions may also be needed.
There are several limitations to this study that the authors acknowledge. First, the girls with ADHD were referred from both psychiatric and pediatric facilities/practitioners, and the degree to which they are representative of girls with ADHD in the general community can not be determined with any certainty. Thus, it is quite possible that the girls in this study were more impaired than would be girls with ADHD from the general population.
In addition, it is clear that research on treatment specifically in girls with ADHD is sorely needed. Currently, most of the data on both medical and non-medical treatment of ADHD is also based predominantly on boys. To my knowledge, there is currently no clear indication of any known differential effect for various treatments that is specifically related to gender, but this may be partially because the studies that are required to carefully look at this issue have not really been done.
Dr. David Rabiner, child psychologist and Senior Research Scientist at Duke University, produces the monthly online newsletter, Attention Research Update, that helps parents, professionals, and educators keep informed about new research on ADHD. To sign up for a free subscription, please visit http://www.helpforadd.com/.