Contrasting monosymptomatic patients with hallucinations and delusions in first-episode psychosis patients: a five-year longitudinal follow-up study.

BACKGROUND: The main aim of this study was to identify subgroups of patients characterized by having hallucinations only or delusions only and to examine whether these groups differed with regard to demographic characteristics, clinical characteristics and outcome factors, including suicidality.
METHODS: Out of 301 consecutively admitted patients with first-episode psychosis, individuals with delusions only (D) and hallucinations only (H) were identified based on Positive and Negative Syndrome Scale (PANSS) items P1 (delusions) and P3 (hallucinations) scores at baseline and through 4 follow-up interviews over 5 years. The subgroups were compared with regard to demographic data, premorbid functioning, duration of untreated psychosis, clinical variables, time to remission and suicidality.
RESULTS: Two groups of patients were identified; H (n = 16) and D (n = 106). 179 patients experienced both hallucinations and delusions (dual symptom group). The H group was significantly younger, had a longer duration of untreated psychosis, poorer premorbid function and better insight than the D group. Notably, the H group scored higher on measures of suicidality, and at 5 years follow-up a significantly higher proportion of patients was lost to suicide in this group. The dual symptom group was closer to the D group on significant parameters, including suicidality and suicide rate.
CONCLUSIONS: Patients with hallucinations only can be separated from patients with delusions only and the subgroups differ with regard to demographical data, clinical variables and notably with regard to suicidality. These findings suggest distinctions in the underlying biological and psychological processes involved in hallucinations and in delusions.