Occurrence and Clinical Correlates of Psychiatric Comorbidity in Patients With Psychotic Disorders

Background: The aim of this study was to explorepatterns and clinical correlates of psychiatric comorbidity inpatients with schizophrenia spectrum disorders and mood spectrumdisorders with psychotic features.

Method: Ninety-six consecutively hospitalizedpatients with current psychotic symptoms were recruited andincluded in this study. Index episode psychotic diagnosis andpsychiatric comorbidity were assessed using the StructuredClinical Interview for DSM-III-R-Patient Version (SCID-P).Psychopathology was assessed by the SCID-P, Brief PsychiatricRating Scale, Scale for the Assessment of Negative Symptoms, andHopkins Symptom Checklist. Awareness of illness was assessed withthe Scale to Assess Unawareness of Mental Disorders.

Results: The total lifetime prevalence ofpsychiatric comorbidity in the entire cohort was 57.3% (58.1% inschizophrenia spectrum disorders and 56.9% in mood spectrumpsychoses). Overall, panic disorder (24%), obsessive-compulsivedisorder (24%), social phobia (17.7%), substance abuse (11.5%),alcohol abuse (10.4%), and simple phobia (7.3%) were the mostfrequent comorbidities. Within the group of mood spectrumdisorders, negative symptoms were found to be more frequent amongpatients with psychiatric comorbidity than among those withoutcomorbidity, while such a difference was not detected within thegroup of schizophrenia spectrum disorders. Social phobia,substance abuse disorder, and panic disorder comorbidity showedthe greatest association with psychotic features. An associationbetween earlier age at first hospitalization and comorbidity wasfound only in patients with unipolar psychotic depression.Patient self-reported psychopathology was more severe inschizophrenia spectrum patients with comorbidity than in thosewithout, while such a difference was less pronounced in moodspectrum psychoses.

Conclusion: These findings suggest thatpsychiatric comorbidity is a relevant phenomenon in psychoses andis likely to negatively affect the phenomenology of psychoticillness. Further studies in larger psychotic populations areneeded to gain more insight into the clinical and therapeuticimplications of psychiatric comorbidity in psychoses.