Individuals who are treated for ADHD during childhood may return to services for support and treatment when they are ≥18 years old due to continued ADHD symptoms. The aim of this study was to examine the resumption of ADHD prescriptions in early adulthood in young people with ADHD (aged ≥20 years) whose ADHD prescriptions stopped during adolescence (aged 14–16 years).
Primary-care prescribing data* from the UK Clinical Practice Research Datalink (CPRD) from 2005 to 2013 were used in this study. The sample† for this analysis was from a larger database of patients (n=9390) who had a diagnosis of ADHD recorded based on medical and term codes in UK primary care which map to the International Classification of Diseases 10th Edition. Psychotropic medication, including that for ADHD, was categorised using CPRD product codes referring to the British National Formulary categories. Resumption was defined as having ≥1 recorded prescription of ADHD medication when patients were aged ≥20 years.
Overall, 1440 young people (male: n=1293 [89.8%]) were included in the analysis; 395 (27.4%) had a prescription for a non-ADHD psychotropic medication at any point, 348 (24.2%) had a recorded diagnosis of another psychiatric disorder (excluding learning disability) and 64 (4.4%) had a recorded learning disability. From this sample, only 109 (7.6%, 95% confidence interval [CI] 6.3–9.1%) patients resumed their prescription for ADHD medication when they were aged ≥20 years. Of the females in the study sample, only 17/147 (11.6%) resumed ADHD medication, compared with 92/1293 (7.1%) males.
The rest of the study results were as follows:
- Ages of stopping and resuming ADHD medication
- In total, 427/1440 (29.7%) patients stopped ADHD medication at the age of 16 which was the most common age for medication cessation; 372 (25.8%) and 319 (22.2%) stopped medication at 17 and 18 years, respectively.
- In this analysis, although the majority of patients (92.4%) did not restart medication, for those who did, most restarted medication before the age of 22 (20 years: n=66 [4.6%]; 21 years: n=19 [1.3%]; and 22 years: n=15 [1.0%]).
- For patients who had resumed medication, the median duration of persistence was 1 year (interquartile range: 1–4 years).
- Of the 113 patients who stopped medication at the age of 14, only 6 (5.3%) resumed medication, compared with 42/319 (13.2%) who stopped medication at the age of 18. Therefore, the later the patient stopped ADHD medication in adolescence, the more likely they were to restart a prescription in early adulthood.
- Factors associated with resumption of ADHD medication
- Patients with a recorded referral to adult mental-health services (28/142 [19.7%]), those with a learning disability (12/64 [18.8%]) and those prescribed non-ADHD psychotropic medication (52/395 [13.2%]) had the highest resumption levels. This was followed by patients with: substance misuse (6/35 [17.1%]); anxiety or depression (15/125 [12.0%]); autism spectrum disorders (13/112 [11.6%]); any non-ADHD psychiatric disorder (excluding learning disability; 36/348 [10.3%]); and conduct or oppositional defiant disorder (9/92 [9.8%]).
- The cumulative percentage of prescription resumption increased with age; the estimated probability of resumption at: 1 year was 4.6% (95% CI 3.5–5.8%) by age 20; at 3 years was 7.6% (95% CI 6.3–9.2%) by age 22; and at 5 years was 9.7% (95% CI 7.7–12.0%) by age 24.
- The adjusted Cox regression model for resumption of prescription in patients aged 20–22 years was significantly associated with being female (hazard ratio [HR] 1.81 [95% CI 1.04–3.26], p = 0.05), having a referral recorded to adult mental-health services (HR 2.18 [95% CI 1.30–3.66, p = 0.003), having a learning disability (HR 2.43 [95% CI 1.25–4.74], p = 0.009), having an antipsychotic prescription aged ≥19 years (HR 3.58 [95% CI 1.86–6.88, p < 0.0001) and stopping medication between the ages of 17 and 18 versus 14 and 16 (HR 2.04 [95% CI 1.28–3.24, p = 0.003).
- Compared with patients who did not resume ADHD medication, prescription of non-ADHD psychotropic medication (including antidepressants [17.1% vs 33.0%, p < 0.0001], antipsychotics [10.2% vs 20.2%, p = 0.001], anxiolytics/hypnotics [5.2% vs 11.9%, p = 0.003]) was higher in those who did resume ADHD medication, and for those who took multiple non-ADHD prescriptions (resumption: 16/109 [14.7%] vs no resumption: 79/1331 [5.9%], p < 0.0001).
This study has several limitations that must be considered. Although the CPRD database is broadly representative of the UK population, the authors acknowledge that this study is likely to have underestimated the resumption of ADHD medication to some extent as in some cases ADHD medication is resumed and prescribed solely in specialist services or by private psychiatrists. Moreover, recordings of secondary care referrals was low which suggests that this may have been under-recorded which limits the conclusions that can be made regarding the level of specialist support for medication resumption. In this analysis there is also no way of knowing if patients who resumed their prescription medication actually took it, and there were no data on the symptoms or severity of ADHD recorded in the CPRD database.
To conclude, the authors indicate that these data suggest that most individuals who stop their ADHD medication in adolescence do not have their prescriptions resumed in early adulthood. These findings highlight that current models of care and prescribing may not be suitable and flexible enough for young adults with ADHD, and primary care may not be adequately supported by specialist services in managing ADHD in young adulthood.
*The primary-care section of the database contains the records of >11 million patients and is contributed to by 670 general practitioner practices across the UK
†To be included in this analysis, patients had to have: ≥1 years’ worth of prescribing records for ADHD medication (to ensure that this was a regular prescription and not a ‘trial’ medication); their last recorded prescription for ADHD medication issued between the ages of 14 and 18, with no further ADHD prescribing record until the age of 20, if at all; and ≥1 years’ worth of follow-up data in the CRPD from the age of 20
Newlove-Delgado T, Ford TJ, Hamilton W, et al. Resumption of attention-deficit hyperactivity disorder medication in early adulthood: findings from a UK primary care prescribing study. Eur Child Adolesc Psychiatry 2019; Epub ahead of print.