Factor analysis of the Frankfurt complaint questionnaire in a Spanish sample

The Frankfurt Complaint Questionnaire (FCQ) is a self-assessment instrument designed to evaluate the subjective experiences (SE) of psychotic patients, It is composed of 98 yes-no items grouped in ten phenomenological subscales. The original validation of the FCQ included a factor analysis with a four-factor structure. No further studies of factor validity have been carried out. The present study aimed to replicate the factor structure of the FCQ in a Spanish sample. The sample was composed of 286 consecutively admitted patients due to a recrudescence of their psychotic symptoms. They were evaluated through a semistructured interview for schizophrenia and diagnosed according to DSFVI-III-R criteria. Organic mental disorders were excluded, Sixteen patients who failed to fulfill the FCQ were excluded. The sample finally comprised 270 patients. A factor structure of FCQ items comprising 25 factors was found. The first factor obtained the highest explained variance, and most items obtained their highest load on the first factor. These results strongly suggest a unidimensionality underlying FCQ items. A new scale composed of 18 items was derived from those with higher weights in the first factor. The new scale of SE was presented in a Likert format to demonstrate their frequency and intensity more clearly.