[Stability of the factorial structure of the AMP system during treatment]

The stability of the factorial structure of the AMP system was studied during the course of psychopharmacological treatments (day 0, 5, 10, 20) of 396 patients mainly suffering from endogenous psychoses. The analysis was based on a reduced item pool of 52 items, which occurred on day 20 in at least 10% of the patients. For the 9-factor solution the factorial structure was stable during treatment for the apathetic, the hallucinatory-desintegrative and the retarded-depression syndrome as well as for the hostility syndrome. The other five AMP syndrome showed no stable structure during the treatment. On the other hand the factorial structure of the 2-factor-solution was found to be stable on day 0, 5, 10 and 20 without exception. These results should be considered when using the AMP system for the documentation of syndromes during the course of therapeutic trials.