The Criteria of diminished responsibility still are not defined. The aim of research is determination of the factor “Situation” for specification of the criteria of diminished responsibility.

Cohort of 300 patients were studied by clinical psychopathological methods.

So, all kinds of mental disorders of non-psychotic level can be considered as a medical criterion of diminished responsibility, especially in the cases when the role of the factor “Situation” is minimal. For impartial point of view we offer to use an estimation of social adaptation.

Even if the role of the factor “Situation” is minimal, we have to analyze it especially in the cases of group crimes of mentally retarded and infantile patients because of such their characteristics as suggestiveness and striving for self-affirmation in referent group.

When patient commit a crime during traumatic situation, his psychic disorders become a basis of various pathological mental states which can influence on ability of voluntary regulation of behavior. Among these states are various affective disorders from depressions to dysphoria, emotional instability, acute affective outbreaks in a patients with personality disorders in frameworks of mental retardation, organic disease, remission of schizophrenia.