A new study published in the journal European Psychiatry indicates that adult women with attention-deficit/hyperactivity disorder (ADHD) tend to experience more severe symptoms and greater impairment in daily life compared to men with the condition. The research also uncovered a significant delay in the diagnosis of ADHD for women, which may contribute to these more challenging outcomes.
The investigation was prompted by growing recognition that ADHD affects individuals differently, particularly across sexes. While historically viewed as a condition predominantly affecting boys, it is now understood that ADHD persists into adulthood for many and that women are often underdiagnosed.
Researchers led by Ferran Mestres sought to clarify how sex and the specific subtype of ADHD influence the disorder’s severity, its connection to other mental health conditions, and its impact on a person’s ability to function in daily life. By examining these factors, the team aimed to build a more detailed understanding that could help improve diagnosis and treatment for different patient groups.
To conduct their research, the scientific team recruited 900 adults who had been diagnosed with ADHD at a specialized clinic at the Vall d’Hebron University Hospital in Barcelona, Spain. Of the participants, just under 55 percent were male. Each individual underwent an extensive evaluation process that spanned five separate visits with psychiatrists and psychologists specializing in ADHD. This comprehensive assessment confirmed their ADHD diagnosis and determined their specific presentation, which can be predominantly inattentive, predominantly hyperactive-impulsive, or a combination of both.
Participants also completed a wide range of validated questionnaires and assessments. These tools were used to measure the intensity of their ADHD symptoms, both currently and during childhood. The evaluations also gauged levels of depression, anxiety, and impulsivity. Additional instruments assessed sleep quality and the disorder’s effect on psychosocial functioning and overall disability. The researchers then used statistical methods to compare the results between men and women and between different ADHD subtypes. They also analyzed how sex and subtype might interact to influence outcomes.
The study’s findings revealed notable differences between men and women. One of the most significant discoveries was the age of diagnosis. Although symptoms of ADHD appeared to begin at a similar age for both sexes, women received their diagnosis much later, at an average age of about 29 years, compared to an average age of 24 for men. At the time of their diagnosis, women reported more severe overall ADHD symptoms than men.
Beyond the core symptoms of ADHD, women in the study also experienced higher rates of other mental health challenges. They scored higher on measures of both depression and anxiety compared to their male counterparts. Functionally, women reported greater impairment in their social and professional lives and a higher degree of disability, suggesting the disorder had a more substantial negative effect on their day-to-day activities. In contrast, men with ADHD were more likely to have a history of legal problems and reported significantly higher rates of substance use, including alcohol, tobacco, and cannabis.
Silvia Amoretti, a senior researcher involved in the study, commented on the findings. “ADHD affects millions of people, but our understanding of how it presents and impacts males and females differently remains limited. We found that females are underdiagnosed, often receiving a diagnosis years later than males. This delay may lead to worse clinical outcomes, including depression, anxiety, and functional impairment.
Males on the other hand showed a higher level of involvement in delinquent behaviours such as legal problems and driving-related difficulties. We believe that a better understanding these sex-based differences might improve diagnosis and treatment.”
The researchers also examined differences based on ADHD subtype. The combined presentation, which involves symptoms of both inattention and hyperactivity-impulsivity, was linked to more severe outcomes overall. Individuals with the combined subtype had more intense ADHD symptoms, higher levels of depression, anxiety, and impulsivity. They were also more likely to engage in substance use and experience legal troubles compared to those with the predominantly inattentive subtype.
The team then explored whether a person’s sex and their ADHD subtype interacted to produce unique outcomes. For most of the clinical measures, this was not the case, suggesting that the effects of sex and subtype were largely independent. However, one specific interaction emerged for disability. Women with the combined ADHD subtype reported the highest level of disability of any group, showing more significant impairment than men with the same subtype and more than individuals of either sex with the inattentive subtype.
The study authors propose several potential reasons for this specific finding. The interaction could be influenced by biological factors, such as the effect of female hormonal cycles on brain chemicals involved in attention and emotional regulation. Psychosocial factors, including societal expectations for women regarding organization and emotional control, may also play a part. The accumulated stress from years of unrecognized and untreated symptoms due to delayed diagnosis could also contribute to this heightened sense of disability in women with the combined presentation.
“We found that although ADHD symptoms started at a similar age in males and females, women were diagnosed about five years later. By the time of diagnosis, they showed more severe symptoms, worse functioning in daily life, and higher rates of depression and anxiety,” Amoretti said.
“This is important because it shows that ADHD often goes unnoticed in women until it becomes a serious problem. Our findings suggest that we may be missing the early signs in girls and women, especially when their symptoms are less disruptive but still impactful. This has clear implications for earlier screening and sex-sensitive diagnostic tools,” she continued.
“We didn’t set out to compare the age of diagnosis in males and females, we were aiming to understand the general age when symptoms appear, regardless of sex. This finding was not part of our initial hypotheses but became evident during the analysis, and the scale of the difference in diagnosis between the sexes was a surprise.”
“It’s likely that women are diagnosed later because the symptoms of ADHD manifest themselves differently in men and women. Boys are more likely to be hyperactive or impulsive, and this behaviour is more visible to parents, teachers and clinicians. On the other hand, girls with ADHD are more likely to seem inattentive and generally less disruptive. This becomes clinically important, as it means that women are just not treated early enough, and often are just not diagnosed at all. We have seen similar tendencies internationally, so it is likely that this is a global problem. The nature of the condition leads to poorer diagnosis in women everywhere, meaning that women can lose on average five years of treatment, 5 years of a better life,” Amoretti concluded.
Professor Sandra Kooij, an independent expert who was not involved in the study, commented on the research. “This study by Sylvia Amoretti and colleagues shows the delay in diagnosis in girls and women with ADHD compared to boys and males. Different presentation of symptoms, lack of awareness among clinicians that women have ADHD too, and the hormonal changes leading to severe mood instability in the last week of the cycle are all responsible for the gender differences in time to diagnosis of ADHD. Increasing awareness in both society and medicine helps girls and women to get earlier help when they need it.”
The authors of the study noted some limitations. The participants were recruited from a specialized treatment center, so the findings may not be fully representative of all adults with ADHD. The study design also captures a snapshot in time and cannot determine cause-and-effect relationships. Even with these considerations, the large sample size and the use of multiple validated tools provide strong evidence for the different ways ADHD can manifest.
Future research could follow individuals over time to better understand these dynamics and explore how factors like socioeconomic status or biological conditions might interact with sex and subtype to shape ADHD outcomes.
The study, “Sex differences in adults with attention-deficit/hyperactivity disorder: A population-based study,” was authored by Ferran Mestres, Vanesa Richarte, Juan Jesús Crespín, Carla Torrent, Santiago Biel, Carolina Ramos, Pol Ibáñez, Laura Oltra-Arañó, Montse Corrales, Silvia Amoretti, Christian Fadeuilhe, and Josep Antoni Ramos-Quiroga.
