Objective versus subjective assessment of MPH response

Abstract

The main pharmacotherapy of Attention Deficit Hyperactivity Disorder (ADHD) is stimulants, especially methylphenidate (MPH). MPH efficacy is assessed by subjective measures. The Test of Variables of Attention (TOVA) is a known objective assessment measure. In order to assess the accuracy of patients' reports, we used Clinical Global Impression – Compared (CGI-C-C) before and after MPH challenge comparing to the objective TOVA alterations.

165 children and adolescents, who were referred to the ADHD unit and were diagnosed as ADHD were included. TOVA was done before and after MPH challenge (0.3 mg/Kg). All patients filled CGI-C-C blind to the TOVA results.

165 patients participated in the study, M:F ratio 67%:33% respectively. Average age was 11.09+3.43 yrs. ADHD mixed type: ADHD inattentive type, 50.6%:48.1% respectively. A significant inverse correlation was found between CGI-C-C and the Commission (C) score of TOVA (r=-0.32, p< 0.01), but not for any of the other scores. Age had a significant role in the accuracy of estimation. A significant negative correlation between the age and the tendency to assess improvement was found (r = -.210, p<0.01). There were no differences by gender or diagnosis. A dependence was found between consistent normal results of ADHD score change and self assessment of improvement (F = 4.22, p<0.05).

A partial correlation was found between subjective and objective measures with regard to response to MPH, mostly for the behavioral aspects. The older the patient the more likely he/she is to estimate improvement, but the role of a placebo effect cannot be ruled out.