ADHD in females often goes undiagnosed or is diagnosed later than in males due to differences in symptom presentation and societal expectations.
Females may exhibit more inattentive symptoms and less hyperactivity, which can be mistaken for other conditions or overlooked entirely.
This delay in diagnosis can lead to missed opportunities for early intervention and support, potentially impacting academic, social, and emotional development.
Researching this area is crucial to improve diagnostic criteria, raise awareness, and ensure timely, appropriate treatment for females with ADHD, ultimately enhancing their quality of life and long-term outcomes.
Skoglund, C., Sundström Poromaa, I., Leksell, D., Ekholm Selling, K., Cars, T., Giacobini, M., Young, S. & Kopp Kallner, H. (2024). Time after time: failure to identify and support females with ADHD–a Swedish population register study. Journal of Child Psychology and Psychiatry, 65(6), 832-844. https://doi.org/10.1111/jcpp.13920
Key Points
- Females receive an ADHD diagnosis approximately 4 years later than males (23.5 vs 19.6 years old on average).
- Females with ADHD show higher rates of psychiatric comorbidity, psychotropic medication use, and healthcare utilization compared to males with ADHD and female controls.
- The study found significant gender differences in ADHD presentation, with females more likely to have predominantly inattentive type ADHD.
- Results indicate potential barriers to evidence-based care for females with ADHD, including diagnostic delays and higher comorbidity burdens.
- This research highlights the need for improved early detection and gender-specific approaches to ADHD diagnosis and treatment.
Rationale
Attention deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder associated with various adverse health outcomes across the lifespan (Faraone et al., 2015).
Previous research has reported sex differences in ADHD prevalence, with ratios ranging from 3:1 to 16:1 male to female in childhood and adolescence (Novik et al., 2006).
However, these differences decrease in adulthood (Cortese et al., 2016), suggesting many girls and young women with ADHD may remain unidentified during crucial developmental years.
ADHD is linked to increased risk-taking behaviors, emotional and social impairments, accidental injuries, substance use disorders, and academic underachievement (Pollak et al., 2019; Ros & Graziano, 2018; Dalsgaard et al., 2015; Lee et al., 2011; Korrel et al., 2017).
Early detection, diagnosis, and treatment are critical to mitigating these risks. However, there is evidence that females may experience delays in referral and diagnosis compared to males (Klefsjo et al., 2021).
This study aims to explore the hypothesis of diagnostic delay in females and investigate sex-specific factors such as comorbidity, pharmacological treatment, and healthcare utilization patterns before and after ADHD diagnosis.
Understanding these patterns is crucial for ensuring equal access to detection, diagnostic assessment, and treatment for both females and males with ADHD.
Method
This population-based, cross-sectional cohort study used data from the Regional Healthcare Data Warehouse of Region Stockholm (VAL) in Sweden.
The study included all residents in Stockholm County between January 1, 2011, and December 31, 2021, who had at least one record of ADHD diagnosis (ICD-10 code F90) or prescription for ADHD medication during the study period.
Procedure
The study analyzed data from healthcare records and prescription databases. The primary outcome was age at ADHD index (first record of diagnosis or medication).
Secondary outcomes included differences in psychiatric comorbidity, pharmacological treatment, and healthcare utilization between females and males with ADHD, and with population controls, before and after ADHD index.
Sample
The study included 85,330 individuals with ADHD (37,591 females and 47,739 males) and 426,626 matched population controls.
Participants were residents of Stockholm County, aged ≥3 years, with at least 12 months of residency prior to ADHD index.
Measures
- ADHD diagnosis: ICD-10 code F90 or prescription of ADHD medication
- Psychiatric comorbidity: Various ICD-10 codes for conditions like anxiety, mood disorders, substance use disorders, etc.
- Pharmacological treatment: ATC codes for different medication categories
- Healthcare utilization: Inpatient bed-days and outpatient visits for psychiatric and non-psychiatric care
Statistical measures
Descriptive statistics, Pearson’s Chi-square test, independent sample proportion test, Welch two-sample t-test, Mann-Whitney U-test, and binary logistic regression were used for data analysis.
Results
Hypothesis 1: Females are diagnosed with ADHD at a higher age compared to males.
Result: Confirmed. Females had their ADHD index at a median age of 19.0 years (IQR 13.0-32.0), while males had it at 14.0 years (IQR 9.0-28.0). On average, ADHD index was 3.9 years later in females compared to males.
Hypothesis 2: Females with ADHD have higher rates of psychiatric comorbidity compared to males with ADHD.
Result: Confirmed. Females with ADHD showed higher rates of anxiety disorders (50.4% vs. 25.9%), mood disorders (37.5% vs. 19.5%), eating disorders (5.6% vs. 0.6%), and personality disorders (6.3% vs. 2.1%) compared to males with ADHD.
Hypothesis 3: Females with ADHD have higher rates of pharmacological treatment compared to males with ADHD.
Result: Partially confirmed. Females with ADHD showed higher use of anticonvulsants, neuroleptics, sedatives, hypnotics, and psychoanaleptics compared to males with ADHD. However, ADHD medication use was similar across sexes at 2 and 5 years after index.
Hypothesis 4: Females with ADHD have higher healthcare utilization compared to males with ADHD.
Result: Confirmed. Females with ADHD had higher annual proportions of both psychiatric and non-psychiatric healthcare utilization, including inpatient and outpatient care, compared to males with ADHD.
Insight
This study provides strong evidence for a significant delay in ADHD diagnosis for females compared to males, with females being diagnosed nearly 4 years later on average.
This delay could have substantial implications for the development and life outcomes of females with ADHD, as they may miss out on early interventions and support during critical developmental periods.
The research also highlights the higher burden of psychiatric comorbidities in females with ADHD, particularly anxiety and mood disorders.
This finding suggests that the clinical presentation of ADHD in females may be more complex and potentially masked by these comorbid conditions, contributing to diagnostic delays.
The higher rates of psychotropic medication use and healthcare utilization among females with ADHD, both before and after diagnosis, indicate a greater overall health burden.
This could be a result of the delayed diagnosis, with females potentially developing more severe or treatment-resistant comorbidities due to a lack of timely ADHD treatment.
These findings extend previous research by providing a comprehensive, population-based analysis of sex differences in ADHD diagnosis and associated health outcomes.
They underscore the need for increased awareness of ADHD presentation in females among healthcare providers and the development of sex-specific diagnostic and treatment approaches.
Further research could explore the specific factors contributing to diagnostic delays in females, such as differences in symptom presentation or societal expectations.
Additionally, longitudinal studies could investigate the long-term impacts of delayed diagnosis on various life outcomes for females with ADHD.
Strengths
The study had many methodological strengths including:
- Large sample size (85,330 individuals with ADHD) providing robust statistical power
- Population-based design, enhancing generalizability of findings
- Inclusion of matched controls, allowing for comparison with general population
- Comprehensive data on diagnoses, medications, and healthcare utilization from high-quality Swedish registries
- Analysis of data both before and after ADHD index, providing a longitudinal perspective
Limitations
The study has several limitations:
- Geographical restriction to Stockholm County, potentially limiting generalizability to other regions or countries
- Reliance on registered diagnoses and prescriptions, which may not capture all cases of ADHD, especially undiagnosed ones
- Inability to assess functional impairment or severity of disorders beyond diagnostic codes
- Lack of information on private healthcare providers, potentially missing some ADHD cases
- Inability to control for potential confounding factors such as socioeconomic status or family history of ADHD
These limitations imply that the study may underestimate the true prevalence of ADHD, especially in females who might be underdiagnosed.
The results may also not be fully applicable to settings with different healthcare systems or cultural contexts.
Implications
The results of this study have significant implications for clinical practice and public health:
- Diagnostic practices: Healthcare providers should be more aware of the potential for ADHD in females, especially those presenting with anxiety or mood disorders. Screening for ADHD should be considered in females with these comorbidities.
- Early intervention: Given the later diagnosis in females, there’s a need for improved early detection methods. This could involve educating teachers, parents, and primary care providers about the signs of ADHD in girls.
- Treatment approaches: The higher rates of comorbidities in females with ADHD suggest a need for more comprehensive, multi-modal treatment approaches that address both ADHD symptoms and co-occurring conditions.
- Healthcare utilization: The higher healthcare utilization among females with ADHD indicates a need for better coordinated care to manage both ADHD and comorbid conditions effectively.
- Public awareness: There’s a need for increased public awareness about ADHD presentation in females to reduce stigma and promote earlier help-seeking.
- Policy implications: Health policies should consider the sex-specific needs in ADHD care, potentially allocating more resources for female-specific interventions and support services.
- Research focus: These findings highlight the need for more research into female-specific aspects of ADHD, including potential interactions with hormonal cycles and pregnancy.
Variables that may influence these results include societal expectations and gender norms, which may affect how ADHD symptoms are perceived and reported in females versus males.
Additionally, the structure of healthcare systems and access to mental health services could impact diagnosis rates and treatment patterns.
References
Primary reference
Skoglund, C., Sundström Poromaa, I., Leksell, D., Ekholm Selling, K., Cars, T., Giacobini, M., Young, S. & Kopp Kallner, H. (2024). Time after time: failure to identify and support females with ADHD–a Swedish population register study. Journal of Child Psychology and Psychiatry, 65(6), 832-844. https://doi.org/10.1111/jcpp.13920
Other references
Cortese, S., Faraone, S. V., Bernardi, S., Wang, S., & Blanco, C. (2016). Gender differences in adult attention-deficit/hyperactivity disorder: results from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). The Journal of clinical psychiatry, 77(4), 7626.
Dalsgaard, S., Østergaard, S. D., Leckman, J. F., Mortensen, P. B., & Pedersen, M. G. (2015). Mortality in children, adolescents, and adults with attention deficit hyperactivity disorder: a nationwide cohort study. The Lancet, 385(9983), 2190-2196.
Faraone, S. V., Asherson, P., Banaschewski, T., Biederman, J., Buitelaar, J. K., Ramos-Quiroga, J. A., … & Franke, B. (2015). Attention-deficit/hyperactivity disorder. Nature Reviews Disease Primers, 1(1), 1-23.
Klefsjö, U., Kantzer, A. K., Gillberg, C., & Billstedt, E. (2021). The road to diagnosis and treatment in girls and boys with ADHD–gender differences in the diagnostic process. Nordic journal of psychiatry, 75(4), 301-305. https://doi.org/10.1080/08039488.2020.1850859
Korrel, H., Mueller, K. L., Silk, T., Anderson, V., & Sciberras, E. (2017). Research Review: Language problems in children with Attention‐Deficit Hyperactivity Disorder–a systematic meta‐analytic review. Journal of Child Psychology and Psychiatry, 58(6), 640-654. https://doi.org/10.1111/jcpp.12688
Lee, S. S., Humphreys, K. L., Flory, K., Liu, R., & Glass, K. (2011). Prospective association of childhood attention-deficit/hyperactivity disorder (ADHD) and substance use and abuse/dependence: a meta-analytic review. Clinical psychology review, 31(3), 328-341. https://doi.org/10.1016/j.cpr.2011.01.006
Nøvik, T. S., Hervas, A., Ralston**, S. J., Dalsgaard, S., Rodrigues Pereira, R., Lorenzo, M. J., & ADORE Study Group*. (2006). Influence of gender on attention-deficit/hyperactivity disorder in Europe–ADORE. European child & adolescent psychiatry, 15, i15-i24. https://doi.org/10.1007/s00787-006-1003-z
Pollak, Y., Dekkers, T. J., Shoham, R., & Huizenga, H. M. (2019). Risk-taking behavior in attention deficit/hyperactivity disorder (ADHD): A review of potential underlying mechanisms and of interventions. Current psychiatry reports, 21, 1-11. https://doi.org/10.1007/s11920-019-1019-y
Ros, R., & Graziano, P. A. (2018). Social functioning in children with or at risk for attention deficit/hyperactivity disorder: A meta-analytic review. Journal of Clinical Child & Adolescent Psychology, 47(2), 213-235. https://doi.org/10.1080/15374416.2016.1266644
Keep Learning
Socratic questions for a college class to discuss this paper:
- How might societal expectations and gender norms contribute to the observed differences in ADHD diagnosis between males and females?
- What potential long-term consequences could result from the delayed diagnosis of ADHD in females? How might these impact various aspects of life such as education, career, and relationships?
- How could healthcare systems be restructured to better identify and support females with ADHD?
- What role might hormonal influences play in the expression of ADHD symptoms in females? How could this impact diagnosis and treatment?
- How might the higher rates of comorbid conditions in females with ADHD affect treatment approaches? What challenges might this present for healthcare providers?
- What ethical considerations arise from the significant disparity in age of diagnosis between males and females?
- How might the findings of this study influence public health policies related to mental health screening and early intervention programs?
- In what ways could educator training be modified to better recognize signs of ADHD in female students?
- How might the results of this study impact the current diagnostic criteria for ADHD? Should sex-specific criteria be considered?
- What potential biases in the healthcare system might contribute to the delayed diagnosis of ADHD in females, and how can these be addressed?
