The study presents the results of a research aimed at eliminating the problem behaviour of a pupil with dual exceptionalities – intellectual giftedness and attention deficit hyperactivity disorder in the younger school age in the conditions of inclusion. The research was a single-case experimental study. The aim of the research was to verify the effectiveness of a purposefully designed and applied intervention programme for the elimination of problem behaviour of the case – a pupil with intellectual giftedness and attention deficit hyperactivity disorder in the younger school age in the conditions of inclusion. The intervention programme was aimed at strengthening concentration of attention, relaxation and calming, strengthening emotionality and motor skills through psychotherapeutic and experiential activities while working with selected literary texts. The results of the research, interpreted by comparing input and output measures of the case's level of behaviour and attentional focus, indicate a reduction in the manifestation of problem behaviour and an increase in attentional focus. According to the CTQ – Conners Teacher's Rating Scale, there were positive changes in the following factors: non-attendance, passivity, tension, anxiety, hyperactivity, behavioural disturbance; according to the CPRS-48 – Conners Parent's Rating Scale, there were positive changes in the following factors: learning difficulties, impulsivity-hyperactivity, behaviour I.

Keywords: Problem behaviour, concentration, pupil with intellectual giftedness and attention deficit disorder, younger school age, single-case experimental study, intervention programme, school inclusion.