ADHD can result in risky sexual behaviour, which in turn, is associated with adverse outcomes including sexually transmitted infections, non-spontaneous abortions and teenage parenthood. The primary aim of the current study was to investigate whether individuals with ADHD in Denmark would be more likely to become teenage parents compared with individuals without ADHD.
This population-based historical prospective cohort study analysed the nationwide population, defined as all individuals born in Denmark from 1 January 1960 to 31 December 2001 who were alive and residing in Denmark on 1 January 1980 or at their 12th birthday, whichever came last. Individuals were defined as having ADHD if they were diagnosed according to the International Statistical Classification of Diseases and Related Health Problems, 8th Revision (ICD-8) or 10th Revision (ICD-10) after inpatient or outpatient treatment at psychiatric, paediatric or neurologic departments in Denmark.
The study analysed the dataset to answer the following questions in comparison with people without ADHD:
- Are individuals with ADHD more likely to become parents while being teenagers?*
- Are individuals with ADHD more likely to become parents in general?†
- Are individuals with ADHD who have children more likely to have many children?‡
- Do individuals with ADHD on average have more or fewer children?§
The dataset included 2,698,052 individuals (1,384,334 male; 1,313,718 female), with a total of 27,479 (20,093 male; 7386 female) diagnosed with ADHD. The following results were reported for each of the outlined questions:
- Likelihood of teenage parenthood
- Individuals with ADHD were significantly more likely to become parents at age 12–16 years (incidence rate ratio [IRR] for females: 3.62, 95% confidence interval [CI] 2.14–6.13; IRR for males: 2.30, 95% CI 1.27–4.17) and at age 17–19 years (IRR for females: 1.94, 95% CI 1.62–2.33; IRR for males: 2.27, 95% CI 1.90–2.70), but significantly less likely to become parents at the age of ≥25 years.
- Likelihood of becoming parents in general
- Those with ADHD were significantly less likely to become parents than those without ADHD; IRRs for becoming a parent were 0.56 (95% CI 0.53–0.60) for males with ADHD and 0.70 (95% CI 0.64–0.76) for females.
- Likelihood of having more children
- Males with ADHD were significantly less likely to progress from having child 1 to child 2 (IRR 0.53 [95% CI 0.49–0.58]), but significantly more likely to progress from having child 3 to child 4 (IRR 1.49 [95% CI 1.17–1.90]) compared with males without ADHD.
- Similarly, females with ADHD were significantly less likely to progress from having child 1 to child 2 (IRR 0.50 [95% CI 0.44–0.57]), but significantly more likely to progress from having child 4 to child 5 (IRR 1.67 [95% CI 1.05–2.65]) than females without ADHD.
- Average number of children
- Males with ADHD had significantly more children than males without ADHD by 20 (mean children in males with ADHD and without ADHD: 0.02 [95% CI 0.02–0.03] and 0.01 [95% CI 0.01–0.01], respectively) and 25 (0.19 [95% CI 0.18–0.21] and 0.14 [95% CI 0.14–0.15], respectively) years of age, but had significantly fewer by 30 (0.52 [95% CI 0.48–0.56] and 0.62 [95% CI 0.62–0.62], respectively), 35 (0.90 [95% CI 0.83–0.96] and 1.24 [95% CI 1.24–1.24], respectively) and 40 (1.12 [95% CI 1.02–1.21] and 1.59 [95% CI 1.59–1.59], respectively) years of age.
- Females with ADHD had significantly more children than those without ADHD by 20 (mean children in females with ADHD and without ADHD: 0.07 [95% CI 0.05–0.08] and 0.04 [95% CI 0.04–0.04], respectively) and 25 (0.45 [95% CI 0.40–0.49] and 0.33 [95% CI 0.33–0.33], respectively) years of age on average, but both groups had a similar number of children by 30 (0.98 [95% CI 0.89–1.07] and 1.00 [95% CI 1.00–1.01], respectively), 35 (1.65 [95% CI 1.53–1.77] and 1.63 [95% CI 1.62–1.63], respectively) and 40 (1.83 [95% CI 1.69–1.96] and 1.88 [95% CI 1.88–1.89], respectively) years of age.
When adjusted for multiple factors,|| the differences reported for questions 1–3 remained significant, with the exception that females with ADHD were not significantly more likely to progress from having child 4 to child 5 in the adjusted analysis.
Limitations of the study primarily stemmed from the lack of control over the dataset. By using a register-based definition of ADHD, potential issues regarding the reliability of diagnosis and changes to the diagnosis over the years were introduced. Also, the dataset may fail to include some patients diagnosed in private practices, where psychiatrists and paediatricians do not report ADHD diagnoses to the registers.
The authors concluded that individuals with ADHD are significantly more likely to become parents during teenage years compared with those without ADHD. They therefore felt that this group presents a good focus for targeted sexual education.
Read more about Danish teenage parenthood and pregnancy in those with ADHD here
*IRRs were calculated for having a child within the following age intervals in female participants: 12–16, 17–19, 20–24, 25–29, 30–34 and ≥35 years; and within the following intervals in male participants: 12–16, 17–19, 20–24, 25–29, 30–34, 35–39 and ≥40 years
†IRRs were calculated to reflect the likelihood of females and males diagnosed with ADHD becoming parents compared with those without ADHD
‡IRRs were calculated for the progression from having child 1 to child 2, from child 2 to child 3, from child 3 to child 4, and from child 4 to child 5
§The average number of children that female and male participants with/without ADHD had by 20, 25, 30 and 40 years of age was calculated
||Parental history of mental disorders, parental education level, parental occupation status, and comorbid ODD or CD, SUD, bipolar disorder or schizophrenia of the cohort members
Østergaard SD, Dalsgaard S, Faraone SV, et al. Teenage parenthood and birth rates for individuals with and without attention-deficit/hyperactivity disorder: a nationwide cohort study. J Am Acad Child Adolesc Psychiatry 2017; 56: 578-584.