Hallucinogenic drug induced states resemble acute endogenous psychoses: results of an empirical study

Clinical evidence suggests that hallucinogenic drug-induced altered stares of consciousness (ASCs) and the incipient, acute stages of endogenous psych oses share many common phenomenological features. The aim of our study was to assess hallucinogen-like phenomena in endogenous psychotic patients usin g standardised methods. We examined 93 endogenous psychotic patients, 50 he althy controls and a small group of drug induced psychotic patients (n = 7) with two ASC self-assessment scales (questionnaire APZ =Abnormer Psychisch er Zustand = Altered State of Consciousness [Dittrich et al, 1985]; and que stionnaire OAV = Abbreviation of the three subscales: Oceanic Boundlessness /Angst = Dread of Ego Dissolution/Visionary Restructuralisation [Bodmer 198 9]). Patients were examined shortly after remission of their last acute psy chotic episode and they answered the questionnaires referring to the early phase of this episode. Differences in the questionnaire scores were signifi cant between psychotic patients and controls. Drug induced patients had num erically higher scores than endogenous psychotic patients, however these di fferences were only significant for the APZ total score and the undifferent iated items of the APZ, but not for the three APZ subscale and the OAV scor es. 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 questi onnaires correlated significantly with BPRS Factor 3 (thought disturbance). Our results support the hypothesis that hallucinogen-like experiences repr esent common phenomena during the acute stages of endogenous psychoses. Rem arkably, these phenomena include subjectively pleasant experiences of the O SE dimension. In the routine clinical assessment of endogenous psychotic pa tients experiences of this dimension may be more easily overlooked than the negative experiences of the AIA dimension (AIA: Angst vor der Ich-Auflosun g = dread of ego dissolution). (C)1998 Elsevier, Paris.