ADHD In Girls
Taken from ADHD Research Update By David Rabiner, Ph.D. Duke University
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 2
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 4 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 16 times more
likely to have repeated a grade in school, and almost 10 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.
The parents of girls with ADHD also described their family life as
less cohesive and reported greater amounts of conflict with their
daughters.
CLINICAL IMPLICATIONS
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. As you may recall from a study recently
reviewed in ADHD RESEARCH UPDATE, 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 as is true for boys, evaluation 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.