Test-retest reliability of the Frankfurt Complaint Questionnaire

Long-term reliability of the Frankfurt Complaint Questionnaire (FCQ) was investigated in two follow-up studies of participants with psychosis using a test-retest method. In the first study (N = 56), the duration of the follow-up ranged from 6 months to 2 years; Spearman rho was .62 for the abridged (18 items) Spanish version of the questionnaire. In Study 2 (N = 21), in participants with stable schizophrenia, the follow-up ranged from 8 to 11 years; test-retest Spearman rho was .83 for the French version of the questionnaire. Subjective experiences could constitute, in psychosis-prone people, traits or markers of psychotic vulnerability.