The APZ questionnaire was developed in order to explore hypotheses on ASCs. First -- in a series of 11 experiments using different induction methods on N = 393 healthy subjects -- the hypothesis was tested that ASCs have major dimensions in common irrespective of the mode of their induction. In the International Study on Altered States of Consciousness (ISASC) the external validity of the experimental results was assessed. The ISASC was carried out on a total of N = 1133 subjects in six countries. The main results of the experimental studies were corroborated in the field studies. The results can be summarized as follows: the common denominator of ASCs is described by three oblique dimensions, designated as "Oceanic Boundlessness (OSE)", "Dread of Ego Dissolution (AIA)" and "Visionary Restructuralization (VUS)". The reliability and validity of the scales are satisfactory. Tested versions of the APZ scales are available in English (UK, USA), German, Italian and Portuguese. Psychometrically as yet untested versions exist in Dutch, Finnish, French, Greek, Spanish and Russian. The APZ questionnaire has become the international standard for the assessment of ASCs, thus helping to integrate research. A psychometrically improved version exists in German (OAV questionnaire). The BETA questionnaire, which measures the dimensions "Vigilance Reduction (VIR)" and "Auditive Alteration (AVE)" is also available in German. These dimensions are most likely etiology-dependent.

1. In spite of the wide-spread use of antidepressants during psychotic episodes, it is still true that the course of endogenous affective psychoses is characterized by a decrease of the average duration of the cycles with the increase in the number of episodes. In bipolar manic-depressive psychoses as well as in schizo-affective psychoses every subsequent cycle is shorter by 10 % than the previous one. The corresponding percentage for recurrent depression is 20 %. As schizo-affective and bipolar manic-depressive psychoses start with much shorter cycles, they definitely take a more malignant course than recurrent depression. 2. These courses can not be modified in severely depressed patients by long term Imipramine treatment. In spite of this medication the cycles get shorter and the rate of admissions to a hospital increases. 3. Lithium has genuine prophylactic properties. This result is based on 50 patients from Zurich and 41 patients from Prague. It increases the length of cycles significantly and decreases the rate of admissions by about a third when equal periods of time before and under Lithium medication are compared. It has prophylactic effects on the following diagnostic groups: schizo-affective psychoses, bipolar manic-depressive psychoses and endogenous recurrent depression. The results of Baastrup and Schou (1967) are thus confirmed by two other independent investigations.

170 hospitalised patients (96 schizophrenic, 71 depressive, and 3 manic) were examined using the German version of the CPRS. Based on factor analytical results four subscales (‘manic syndrome’, ‘schizophrenic syndrome’, ‘depressive syndrome’, and ‘side-effects’) and two second-order scales (‘manic-depressive syndrome’ and ‘schizophrenic syndrome’) were constructed. The first three subscales show a good reliability. The fourth subscale (‘side-effects’) has an unsufficient internal consistency, mainly due to the small number of items (6). The two subscales ‘schizophrenic syndrome’ and ‘depressive syndrome’ and the two second-order scales can differentiate very well between schizophrenic and depressive syndromes. The validity of the first and fourth subscale could not be examined in this study.

The interrater reliability of the AMP system and the Comprehensive Psychiatric Rating Scale (CPRS) was compared in a sample of 30 hospitalized schizophrenic or depressive patients. The CPRS proved to have on average a slightly higher reliability on both the level of items and primary scales. The reliability of the secondary scales was nearly identical.

The interrater reliability of the German version of the CPRS was examined in 30 patients (18 schizophrenic, 11 depressive and 1 manic). All patients were examined by the same two raters. The agreement of 55 out of 65 items was determined using the kappa coefficient. Kappa was calculated concerning symptom present/not present and difference ≤ 2/difference > 2. 49 or 54 items show a moderate to excellent agreement. Items based on self-rating have a better interrater reliability than items based on the rating of the psychiatrists. The interrater reliability of the syndromes was calculated, using the rank correlation coefficient. The agreement concerning the 4 primary and the 2 second-order factors is high or excellent. The good results show the usefulness of the CPRS for the assessment of psychopathological findings.