: This paper studies the contribution of anxiety in origin of functional behavioural disorders of children. The intense sensing of anxiety attributes to the shaping of one's personality. Adaptation and adjustment, accommodation and assimilation to stressful conditions producing anxiety are analyzed. There are diagnosed reactions of organism to the circumstances of the CAN syndrome and trauma. In these circumstances, a primary perception of reality is at stake that consequently leads to sociopathological features. This paper also provides the authors' opinions of psychoanalytical and behavioural schools on origin of personal decompensation and neurotic disorders. Causes of panic disorder and other diseases, in which a stress trauma plays a role, are considered. For these reasons the authors suggest classifying the CAN syndrome as a separate nosologic unit in the future ICD-11.