Attention Deficit Hyperactivity Disorder (ADHD) is characterised by inattention, hyperactivity and impulsivity. Working memory correlates with inattention, but the theoretical background is unclear as to whether complex or only verbal working memory alone is an indicator. The first aim was to clarify this aspect. Pharmacotherapy reduces the symptoms of ADHD, but in practice we find, that parents often refuse it. The second aim was to highlight the differences between attentional concentration performance and behavioural symptoms in the light of pharmacotherapy. A battery of tests was used as a research tool. Verbal working memory was measured with the Non-Word Repetition Test and the Digit Span Test, complex working memory with the Listening Span Test and the Reverse Digit Span Test, attentional concentration with the d2-R Test and parents provided us with data using the Conner's Parent Rating Scale. The data were collected from 71 children with ADHD, aged 9-14 years, and they were analysed using a correlation matrix, t-test and linear regression. Scores on verbal and complex working memory tasks were correlated, and verbal working memory scores predicted complex working memory performance. The results also showed that children with ADHD whose parents refused recommended medication had significantly lower attentional performance. Although there were differences in performance, the parents' comments did not indicate this. The results help to specify the diagnostic toolkit of ADHD, support the performance disadvantages of refusing recommended medication, and highlight that parents' inability to objectively assess their child's performance may lead to negative attitudes towards accepting help.