Samples of psychotic patients, first-degree relatives (FDRs) of psychotic, or severely ill patients, treatment-seeking patients, and a random community sample (in all 157 subjects) were assessed by the Structured Interview for Prodromal Symptoms (SIPS) and the SCID-I. Vulnerability to psychosis (VTP) was defined by severity of positive symptoms reported in the SIPS interview and associated with lifetime SCID-I diagnoses.
The number of lifetime diagnoses received increased linearly as the SIPS symptoms approached more psychotic-like phenomena. All VTP subjects received on average 2.5, and currently prodromal subjects 2.9 lifetime SCID-I diagnoses, while the corresponding figure for non-VTP subjects was 0.7 (p<0.0001). Mood disorders and comorbid anxiety disorders were particularly common.
Vulnerability to psychosis seems to be associated with a high number of lifetime Axis-I diagnoses. Occurrence of anxiety disorders is remarkable, and most VTP subjects can be diagnosed with a lifetime mood disorder. VTP subjects require careful assessment of mood and anxiety symptoms and adequate treatment for their multiple disorders.