To compare various methods of visual stimulation (threshold and subthreshold) in psychophysiological diagnosis of paraphilias.

A total of 45 male sexual offenders were examined. All of them look through abnormal sexual photos. Physiological reactions such as skin-galvanic, cardiovascular, muscular reactions, and changes in chest and diaphragmatic respiration/breathing were recorded. During subthreshold stimulation slides' exposition time with masked image was 10 ms. During threshold stimulation slides' exposition time without masked image was 5000 ms. Psychophysiological examination's data were compared with results of clinical interview.

Two patients's groups were studied: with paraphilias (27 pts) and without paraphilias (18 pts). In the first group the concurrency of threshold stimulation data was observed in 88,9 % of cases, at subthreshold stimulation - in 77,8 %. In 37 % at one method stimulation we were observed reactions to stimulus, relevant to paraphilias, on which reactions at the other method were absent. Only at subthreshold stimulations appeared reactions to those stimulus which were submitted in behavior, but not in imaginations and dreams. In these cases realization sexual perversion on altered states of consciousness, and in a post-criminal period was observed the parcial amnesia. In the second group more than in half of cases were marked reactions only for normative sexual stimulus.

The threshold and subthreshold stimulations' data supplement each other in paraphilias' diagnosis.