Objectives:
The aim of the study was to assess schizotypy by using the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE), in the groups of patients with schizophrenia, bipolar disorder (BD) and unipolar (recurrent) depression (UD). An important element of the study was to compare – in terms of similarity – the results obtained in schizophrenia and BD, and – in terms of differences – the results obtained in BD and UD.

Methods:
The study involved 58 patients with schizophrenia (35 men, 23 women, mean age = 34.0, SD = 9.8), 52 patients with BD (22 men, 30 women, mean age = 40.3, SD = 13.6) and 57 UD patients (24 men, 33 women, mean age = 50.2, SD = 11.9), treated in the Department of Adult Psychiatry, Poznan University of Medical Sciences. For the assessment of schizotypy, the full version of the O-LIFE questionnaire (104 questions) was used, including such dimensions as: unusual experiences, cognitive disorganization, introvertive anhedonia and impulsive nonconformity.

Results:
The biggest differences between diagnostic groups were found in the dimensions of unusual experiences and impulsive nonconformity. Similarities between schizophrenia and BD were found for unusual experiences, cognitive disorganization and introvertive anhedonia. Differences between BD and UD were obtained for unusual experiences and impulsive nonconformity.

Conclusions:
The assessment of schizotypy in three diagnostic groups (it was the first study in patients with UD), allowed to address contemporary pathogenic and clinical concepts pertaining to similarities between schizophrenia and BD as well as to differences between two types of affective disorders.