Many authors have described early signs of abnormal sexuality as predictors of endogenous psychotic disorders, or their premonitory, initial or manifest symptoms. Differences in clinical presentation of abnormal sexual behaviour (ASB) in different nosologic forms have been discussed.

103 persons that committed sexual crimes were examined during a complex forensic sexologic and psychiatric evaluation to compare a clinic presentation of sexual disorders in different mental disorders (MD). Clinical psychopathological and sexological methods were used. MD was diagnosed primarily during the psychiatric evaluation in 82 cases (79.1%). 26 persons had schizophrenia and schizotypal disorders (F20-F21 in ICD-10, group 1), 35 had MD due to brain damage and dysfunction (F06-F07, group 2), 21 had disorders of adult personality and behaviour (F60-F61, group 3). Diagnostic criteria of ICD-10 (F65) and The Scale of Sexual Dysontogenesis were used to assess the elements of ASB.

Statistic analysis showed that the chance for ASB to precede the clinical presentation of MD is higher in the group 1 (26.9%). ASB emerged later or simultaneously with MD in groups 2 (88.6%, 5.7%) and 3 (80.9%, 14.3%).

Modern schizophrenia pathogenesis theories relate emerging of primary negative alterations to pathology of brain systems that modulate functions of the frontal cortex. Early ASB may be attributed to involving limbic and prefrontal structures into the primary pathologic neurofunctional process. These structures participate in forming of sexual behaviour and primary gender identification. Thus, ASB is a marker of increased risk of endogenous MD and can be used for early diagnostics of the disorders.