An observational study of once-daily modified-release methylphenidate in ADHD: the effect of previous treatment on ADHD symptoms, other externalising symptoms and quality-of-life outcomes

Methylphenidate (MPH) is the most commonly prescribed stimulant for children with ADHD. Data on the effects of different MPH formulations in real-life settings are scarce, and the role of previous therapy on treatment outcome when switching medications has not been well studied. OBSEER was an observational study designed to evaluate the effectiveness and safety of Equasym XL(®) in routine care. This study assessed whether the improvements reported with Equasym XL(®) are influenced by the degree of symptom control achieved with the previous medication. Patients enrolled in OBSEER were stratified by prior treatment (none, MPH-immediate release [IR] once daily [o.d.] [MPH-IR o.d.], MPH-IR repeated [MPH-IR >o.d.] and MPH-MR [modified release] excluding Equasym XL(®)), and changes in ADHD and other externalising symptoms (CGI-S, FBB-ADHD and DAYAS) and quality of life (QoL, KINDL) were evaluated during treatment with Equasym XL(®). A total of 782 patients were analysed. Significant group-by-time interactions were found for all symptom variables analysed, indicating that effects varied by previous medication. For CGI-S and FBB-ADHD total scores, the greatest reductions in ADHD symptoms were observed in the treatment-naïve subgroup, followed (in order) by MPH-IR o.d., MPH-IR >o.d. and MPH-MR. A similar profile was seen for DAYAS ratings for all periods of the day except the evening, when there were no significant differences between subgroups. Similarly, the treatment-naïve and MPH-IR o.d. subgroups showed the greatest improvements in KINDL ratings. Although effects were greatest for treatment-naïve patients, improvements were also observed in the prior treatment subgroups for symptoms and QoL. This suggests that a change to Equasym XL(®) may be beneficial in patients with suboptimal effects on prior medication.