[Schizophrenia simplex, schizotypal disorder and compulsions. Differential diagnostic considerations].

We report on the case of a man, whose psychopathological symptoms markedly varied during different phases of his illness, causing difficulties in applying common diagnostic criteria for schizophrenia. Depending upon each of the predominant symptoms, this resulted in different diagnoses and therapeutic strategies. We also discuss the importance of obsessions and compulsions in differential diagnosis in this case.