The symptomatic distribution in schizophrenia spectrum disorder is heterogeneous. Patients may experience hallucinations, delusions and combinations thereof, in addition to disorganized and negative symptoms. We have previously found that patients with monosymptomatic hallucinations exhibited a different clinical profile than patients with monosymptomatic delusions or combinations of the two; with an earlier age at onset and more suicidal symptoms.

To replicate findings in a new group of patients with schizophrenia spectrum disorders.

A total of 421 consecutive patients with schizophrenia spectrum disorders were included into the study. They were comprehensively assessed by specifically trained psychiatrists or clinical psychologists; using the SCID for DSM-IV for diagnostic purposes, the PANSS to assess current clinical symptoms and CDSS to assess current depression. Lifetime presence of different symptom types was ascertained during the diagnostic interview.

A total of 346 (82%) had experienced both hallucinations and delusion, 63 (15%) had experienced delusions without hallucinations, 10 (2.5%) had experienced hallucinations without delusions and 2 patients (0.5%) had neither but experienced negative and severely disorganized symptoms. Contrary to hypothesis, we did not find any statistically significant differences in age at onset and in clinical symptoms (including suicidality) between these groups. We also did not find any differences in the type of hallucinatory experiences between hallucinating groups.

In a new sample of patients, we did not replicate previous findings of a different clinical profile in patients with monosymptomatic hallucinations. This type of psychotic disorder is relatively rare, which might pose a problem concerning statistical strength.