This article presents the case of a thirteen-year-old boy suffering from autistic disorder. Special attention is paid to the occurrence of social and communicative deficiencies combined with cognitive disturbance which limit possibility of the autistic person to conduct a normal life. The inability to attain the coherence between various development aspects connected with different disharmonies is presented. There are distinctive disorders in respect to socialisation. The difficulties in understanding and anticipating the social environment complexity may disturb the dynamics of behaviour and release the tendency to social withdrawal, isolation and passiveness.