Adherence to ADHD medication is often suboptimal, which can negatively affect treatment outcomes.1,2
How important is compliance? | Professor Peter Hill | Independent Child and Adolescent Psychiatrist, London, UK
A 2016 review by Frank et al identified 41 studies that reported reasons for patient non-adherence to ADHD medication. All studies were published from 1997–2014 and examined ADHD medication adherence over the long term (>1 year) in children, adolescents or adults.
Commonly reported reasons for poor adherence to ADHD medication included:3
- Own wish/remission/don’t need (19.9%)
- Withdrew consent (16.2%)
- Adverse effects (15.1%)
- Suboptimal effect (14.6%).
Adolescents’ perceptions of the degree of stigma associated with ADHD have been reported to affect receptiveness to treatment,4 and multiple daily doses of medication, involving dosing during school hours, may be a source of embarrassment for students with ADHD.1
Clinicians may therefore wish to consider duration of action when prescribing medication. For example, extended-release formulations may carry the advantage of providing coverage across the whole day, eliminating the need for school-time doses, making treatment more private, avoiding the stigma associated with taking medication and thereby helping to improve adherence.5
A range of different treatment formulations are available to clinicians, for example:
- Methylphenidate is available in immediate- and extended-release formulations6-13
- Dexamfetamine is administered as tablets in single or divided doses or as an oral solution14
- Atomoxetine is administered as capsules once or twice daily15
- Lisdexamfetamine dimesylate is administered as a capsule once daily16
- Guanfacine is administered as a tablet once daily.17
Factors influencing adherence to ADHD medication
Psychoeducation and knowledge of a patient’s acceptance of their condition may be helpful in encouraging adherence to medication, particularly in adolescents.18 Taking medication is in itself an attention-demanding task, and adolescents may also benefit from having their medication laid out in a pill box for taking under parental supervision.18 Other important factors that may influence adherence to medication include family stability; self-concept; the need for control; self-motivation; simplified treatment regimens; and low levels of undesirable effects.18
A Canadian study of 53 university students with ADD or ADHD (mean age at diagnosis 14.7 years) reported that participants were adjusting levels of medication adherence on a day-to-day basis, according to perceived benefits and risks.19
The participating students were surveyed on whether they took, or intended to take, all of their ADHD medication as prescribed a) last Tuesday, b) last Saturday, c) next Tuesday and d) next Saturday. The frequency of not taking ADHD medication ‘on purpose’ and ‘because of forgetting’ was also ascertained.19
Students were more likely to take medication for ADHD on weekdays than at the weekend (Figure). Adherence on weekdays was associated with the belief that ADHD medication enhances academic performance and social skills, whereas weekend adherence was influenced by perceived loss of authentic self and negative side effects.19
Adherence rates in university students with ADHD (n=53)19
Data from a Turkish study of 102 adults (aged >18 years) with ADHD found that adherence to ADHD medication was positively associated with a university education (p=0.05) and referral for family history of ADHD (p=0.03).20
Adherence to different ADHD medications
The German Treatment Compliance in Children and Adolescents on ADHD Medication (COMPLY) study investigated rates of adherence to ADHD medication in children and adolescents (aged 6–17 years; n=504) over a 12-month period. At baseline, 247 patients were prescribed psychostimulants, 252 patients were prescribed non-stimulant medication (atomoxetine), and five patients were prescribed both types of medication concomitantly.21
Medication adherence was measured using the Pediatric Compliance Self-Rating (PCSR) instrument and items 1–4 of the Medication Adherence Rating Scale (MARS).21
At 12-month follow-up, medication adherence (PCSR score ≥5) was reported in:21
- 72.2% of the psychostimulant group
- 67.5% of the atomoxetine group.
Mean MARS score declined in both treatment groups:21
- From 3.6 to 3.1 in the psychostimulant group
- From 3.7 to 2.9 in the atomoxetine group.
Overall, there were no significant differences in adherence between patients taking atomoxetine and patients taking psychostimulant medication.21
An analysis of South Korean insurance claims data (2009–2013) assessed the adherence of children and adolescents (aged 6–18 years; n=10,343) to four different ADHD medications.22
Using a medication possession ratio cut-off of ≥80%, adherence was achieved in:22
- 27.5% of patients taking immediate-release methylphenidate
- 30.5% of patients taking extended-release methylphenidate
- 28.1% of patients taking osmotic-controlled release oral delivery system methylphenidate
- 26.7% of patients taking atomoxetine.
Logistic regression analysis indicated no significant difference in adherence between the four available ADHD medication types.22
- Marcus SC, Wan GJ, Kemner JE, et al. Continuity of methylphenidate treatment for attention-deficit/hyperactivity disorder. Arch Pediatr Adolesc Med 2005; 159: 572-578.
- Barner JC, Khoza S, Oladapo A. ADHD medication use, adherence, persistence and cost among Texas Medicaid children. Curr Med Res Opin 2011; 27(Suppl 2): 13-22.
- Frank E, Ozon C, Nair V, et al. Examining why patients with attention-deficit/hyperactivity disorder lack adherence to medication over the long term: a review and analysis. J Clin Psychiatry 2015; 76: e1459-e1468.
- Bussing R, Zima BT, Mason DM, et al. Receiving treatment for attention-deficit hyperactivity disorder: do the perspectives of adolescents matter? J Adolesc Health 2011; 49: 7-14.
- Taylor E, Döpfner M, Sergeant J, et al. European clinical guidelines for hyperkinetic disorder — first upgrade. Eur Child Adolesc Psychiatry 2004; 13(Suppl 1): I/7-I/30.
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- Canadian ADHD Resource Alliance (CADDRA). Canadian ADHD Practice Guidelines. Toronto: CADDRA, 2011.
- Gould ON, Doucette C. Self-management of adherence to prescribed stimulants in college students with ADD/ADHD. J Atten Disord 2016; Epub ahead of print.
- Semerci B, Taskiran S, Tufan E, et al. Factors predicting treatment adherence in patients with adult attention-deficit/hyperactivity disorder: a preliminary study. Atten Defic Hyperact Disord 2016; 8: 139-147.
- Wehmeier PM, Dittmann RW, Banaschewski T. Treatment compliance or medication adherence in children and adolescents on ADHD medication in clinical practice: results from the COMPLY observational study. Atten Defic Hyperact Disord 2015; 7: 165-174.
- Bhang SY, Hwang JW, Kwak YS, et al. Differences in utilization patterns among medications in children and adolescents with attention-deficit/hyperactivity disorder: a 36-month retrospective study using the Korean Health Insurance Review and Assessment claims database. J Korean Med Sci 2016; 31: 1284-1291.