Adverse sexual and reproductive health outcomes in female adolescents with ADHD and their associations with ADHD medication: a Swedish register-based study

• ADHD (attention-deficit/hyperactivity disorder): a neurodevelopmental condition involving attention difficulties, hyperactivity, and impulsivity.

• SRH (sexual and reproductive health) outcomes: here, sexually transmitted infections (STIs) and unwanted pregnancy.

• STI: an infection spread mainly through sexual contact (e.g., chlamydia, HIV).

• Register-based study: research that uses records already collected by national or regional databases, here Stockholm’s healthcare records and the Swedish prescribed-drug register.

• Cohort study: a study that follows groups over time. Here, girls with ADHD were compared with girls without it.

• Matched controls: comparison participants chosen to resemble the ADHD group on key traits (here, sex, birth year, and socioeconomic status).

• Nested case-control study: a design within a cohort. People who had the outcome (cases) are compared with those who did not (controls) on earlier exposure, here, medication use.

• Hazard ratio (HR): how much more (or less) quickly an outcome occurs in one group than another. 1.0 means no difference.

• Odds ratio (OR): how much higher or lower the odds of an outcome are in one group than another. Below 1 means lower odds.

• Adjusted (aHR/aOR): estimates statistically corrected for other factors, such as coexisting conditions.

• 95% confidence interval (CI): the range in which the true value likely lies. A range that excludes 1.0 indicates a statistically significant association.

• Comorbidity: another condition occurring alongside the main one (e.g., anxiety, depression).

• Substance use disorder (SUD): problematic alcohol or drug use that causes impairment.

• Incidence rate / person-years: the number of new cases divided by the total time people were observed. Here, it is shown per 1,000 person-years.

• Dose-response pattern: the effect grows or shrinks as the amount (here, duration) of exposure increases.

• Executive function: mental skills for planning, impulse control, and decision-making.

• Coitus-timed contraception: methods used at the time of intercourse, such as condoms.

1. Do female adolescents with ADHD have a higher risk of STIs and unwanted pregnancy than peers without ADHD?

2. Does this risk depend on coexisting conditions, particularly anxiety, depression and substance use disorder?

3. Is a longer cumulative duration of ADHD medication use associated with lower risk of these outcomes?

The authors note that previous evidence came mostly from small, voluntary or self-reported studies. They also note that earlier findings on medication were mixed (two large studies suggested protection, one smaller study of about 2,000 people found none).

Study population. The cohort covered females aged 4–20 in the Stockholm Region with a new ADHD diagnosis or first ADHD medication dispensation between 2011 and 2021. Of 22,611 identified, 18,776 remained after exclusions. They were matched up to 1:5 to 93,880 girls without ADHD. The median age at baseline was 13 years.

ADHD and risk. By age 20, 1,787 girls with ADHD (29.3 per 1,000 person-years) and 4,779 without ADHD (15.2 per 1,000 person-years) had an adverse SRH outcome.

• The crude HR was 2.00 (95% CI 1.89–2.12). After adjusting for comorbidities, concomitant medications and healthcare use, the aHR was 1.70 (1.59–1.81).

• The association was stronger for unwanted pregnancy (aHR 1.99, 1.83–2.16) than for STIs (aHR 1.60, 1.48–1.73).

Role of comorbidities. Compared with girls with neither ADHD nor the comorbidity:

Group - aHR (95% CI)
ADHD only: 2.00 (1.86–2.15)
ADHD + depression: 2.05 (1.58–2.65)
ADHD + anxiety: 1.61 (1.34–1.93)
ADHD + substance use disorder: 4.68 (3.38–6.48)
ADHD + more than one comorbidity: 2.04 (1.62–2.55)

Risk was therefore elevated even without these comorbidities, and it was highest with substance use disorder.

Medication duration. This analysis compared 1,787 cases with 8,909 controls, all with ADHD. Using ≤1 year of medication as the reference, the adjusted odds of an SRH outcome were:

• 1 to ≤2 years: aOR 0.94 (0.81–1.08), not statistically significant

• 2 to ≤3 years: 0.77 (0.63–0.95)

• 3 to ≤5 years: 0.65 (0.51–0.83)

• >5 years: 0.64 (0.44–0.94)

A spline model supported a progressive, dose-response decline in risk with longer use. Girls with no medication use had lower odds than the ≤1-year group (aOR 0.67, 0.57–0.79). The authors attribute this to unmeasured differences between medicated and unmedicated girls, such as ADHD severity, which they could not control for.

Interpretation. The authors conclude that adolescent girls with ADHD have nearly double the risk of adverse SRH outcomes, independent of psychiatric comorbidity. They link this to a greater perception of benefits (e.g., enjoyment) and a reduced perception of risk. For unwanted pregnancy, they point to poor executive functioning, which may lead to inconsistent use of coitus-timed contraception such as condoms. Women with ADHD may also be more prone to depression on short-acting hormonal contraception (pill, patch, ring), which can lead to discontinuation. Better symptom control through medication may improve consistent contraceptive use.

Why medication may help. The authors suggest that stimulant medication may improve executive function. Longer stimulant use has also been linked to lower substance abuse, and reduced risky alcohol and drug use may contribute to lower SRH risk. The anxiety finding (a trend toward lower risk) is described as hypothesis-generating because of the wide confidence interval.

Comparison with earlier work. A Taiwanese study (Chen et al.) found that medication reduced STIs in men but not women. The authors suggest cultural and healthcare differences may explain this. Sweden has free, confidential youth clinics and abortion without guardian notification, so they argue the results show medication also reduces SRH diagnoses in a liberal, low-stigma setting.

Limitations.

• Medication exposure is based on filled prescriptions, so actual use is unknown.

• ADHD symptom severity could not be controlled for.

• Girls with longer treatment may differ in unmeasured ways, such as severity, family support and health-seeking behaviour.

• Only first-time SRH events were studied, so recurrent outcomes could not be assessed.

• Some doxycycline-defined STIs may be misclassified, although a sensitivity analysis restricted to STI diagnoses gave similar results.

• Only outcomes recorded through healthcare contact were captured, and girls with ADHD had more healthcare contact, which could inflate detection in that group.

The findings are associations from observational data, not proof of cause and effect.

Recommendations. The authors recommend:

• Timely diagnosis and adequate, sustained treatment of ADHD in girls, which they say can reduce negative SRH outcomes in the short and long term.

• That psychiatrists and paediatricians consider adding sexual-health counselling and screening to the care of adolescents with ADHD.

• Attention to treatment continuity and adherence.

• Further studies to replicate the anxiety-related pattern.

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