Clinical evidence suggests that hallucinogenic drug-induced altered states of consciousness (ASCs) and the incipient, acute stages of endogenous psychoses share many common phenomenological features. The aim of our study was to assess hallucinogen-like phenomena in endogenous psychotic patients using standardised methods. We examined 93 endogenous psychotic patients, 50 healthy controls and a small group of drug induced psychotic patients (n = 7) with two ASC self-assessment scales (questionnaire APZ = Abnormer Psychischer Zustand = Altered State of Consciousness [Dittrich et al, 1985]; and questionnaire OAV = Abbreviation of the three subscales: Oceanic Boundlessness/Angst = Dread of Ego Dissolution/Visionary Restructuralisation [Bodmer 1989]). Patients were examined shortly after remission of their last acute psychotic episode and they answered the questionnaires referring to the early phase of this episode. Differences in the questionnaire scores were significant between psychotic patients and controls. Drug induced patients had numerically higher scores than endogenous psychotic patients, however these differences were only significant for the APZ total score and the undifferentiated items of the APZ, but not for the three APZ subscale and the OAV scores. More than 50% of the endogenous psychotic patients answered 26% of the APZ-and 43% of the OAV-items with “yes”. The OAV total score and the OSE (Ozeanische Selbstentgrenzung = oceanic boundlessness) scores of both questionnaires correlated significantly with BPRS Factor 3 (thought disturbance). Our results support the hypothesis that hallucinogen-like experiences represent common phenomena during the acute stages of endogenous psychoses. Remarkably, these phenomena include subjectively pleasant experiences of the OSE dimension. In the routine clinical assessment of endogenous psychotic patients experiences of this dimension may be more easily overlooked than the negative experiences of the AIA dimension (AIA: Angst vor der Ich-Auflösung = dread of ego dissolution).
