Attention deficit hyperactivity disorder (ADHD) is more commonly diagnosed in boys than girls, but research into ADHD in adulthood suggests an almost equal balance between men and women.

About 60 percent of children who experience ADHD in childhood continue to have symptoms as adults. Women are less likely to be diagnosed because the guidelines used in assessment and diagnosis have traditionally focused on males. As with men, undiagnosed and untreated women with ADHD are limited in their potential to do well socially, academically, interpersonally, and in family roles.

Some women only recognize their ADHD after a child has been diagnosed and the woman begins to see similar behavior in herself. Other women seek treatment because their lives spin out of control, financially, at work, or at home.

A lower diagnosis rate among females in childhood could also have come about because girls with ADHD are more likely than boys to have the inattentive form of ADHD, and less likely to show obvious problems. Greater self-referrals among adult women may underlie the more balanced gender ratio.

A 2005 study looking at gender differences in ADHD found higher rates of “oppositional defiant disorder” and “conduct disorder” in males, and higher rates of “separation anxiety disorder” in females, suggesting that internalizing disorders are more common in females and externalizing disorders are more common in males.

In a 2004 survey of perceived gender differences in attention deficit disorder, 82 percent of teachers believed that attention deficit disorder is more prevalent in boys. Four out of ten teachers admitted they have more difficulty recognizing ADHD symptoms in girls. The researchers state, “Gender has important implications in the diagnosis and treatment of ADHD. Responses by people with attention deficit disorder demonstrate gender-specific differences in the personal experience of the condition.” They say “the unique needs and characteristics of girls with ADHD” need greater exploration.

Dr. Joseph Biederman of Harvard Medical School explains, “The scientific literature about ADHD is based almost exclusively on male subjects, and girls with ADHD may be underidentified and undertreated.” His work has found that girls with ADHD were more likely to have conduct, mood, and anxiety disorders, lower IQ and achievement scores, and more impairment on measures of social, school, and family functioning, than girls without ADHD.

He commented, “These results extend to girls previous findings in boys, indicating that ADHD is characterized by dysfunction in multiple domains. These results not only support similarities between the genders but also stress the severity of the disorder in females.”

Several studies have investigated the possible gender differences in adults with ADHD. Overall, the findings remain unclear. However, a recent study found that memory problems were likely due to hyperactive symptoms in men and inattentive symptoms in women.

This supports the long-held notion that women with ADHD tend to have inattentive symptoms, which may lead to internalizing problems and becoming anxious and depressed. Reflecting this difference is the recent evidence that girls with attention deficit disorder are over five times more likely than boys to be diagnosed with depression and three times more likely to be treated for depression before their ADHD diagnosis.

In one study of adults with attention deficit disorder, self-ratings showed a significant difference: adult women with ADHD reported fewer good personal qualities and more problems than men, despite there being no gender differences in IQ, neuropsychological test scores, or parent or teacher ratings of behavior. The researchers say, “Adult women’s self-perception is comparatively poorer than that of adult men.”

A 2002 follow-up study indicated that girls with ADHD tend to have a poorer adult psychiatric outcome than boys. It found a higher risk of mood disorder, diagnosis of schizophrenia, and psychiatric admission among women than men.

Among a group of untreated people with ADHD, abuse and criminality were found to be more common in men, and mood, eating, and physical symptoms were more common in women. The experts carrying out this study say, “Otherwise few sex differences were found. Symptom intensity and subtypes did not differ between the sexes.”

Overall, the research on gender differences in attention deficit disorder (with or without hyperactivity) has not established clear biological differences, but women have a tendency toward different ADHD symptoms and coexisting problems such as anxiety, depression, and substance abuse.

People with ADHD all have different needs and face their own challenges. Some of these differences will be linked to gender. It is important that both women and men receive an accurate diagnosis and therapy to address their individual symptoms and other impairments.