With the aim of investigating a possible biological marker of prognosis in schizophrenia, the relationship between striatal dopaminergic D2 receptor (D2R) density and clinical prognostic factors was studied in an initial sample of nine neuroleptic-naive schizophrenic patients. Previous psychosocial adaptation was evaluated by means of the Premorbid Adjustment Scale (PAS). Based on the four DSM-IV criteria in schizophreniform disorder for good prognosis, patients were divided in two groups: good prognosis if > or =2 criteria were met (n=5) and poor prognosis if <2 criteria were met (n=4). D2R density was assessed by means of 123I-IBZM single photon emission computed tomography (SPECT) and striatum/occipital uptake ratios (S/O). S/O ratios previously obtained from a control group of nine age- and sex-matched healthy volunteers were used for comparison.
Results: Patients with poor prognosis showed a higher S/O ratio (mean=1.94, range=1.93-1.98) than patients with good prognosis (mean=1.64, range=1.52-1.79) and the control group (mean=1.69, range=1.51-1.85) [analysis of variance (ANOVA) F=10.628, df=2, P=.001, post hoc Scheffé P<.005]. PAS scores were significantly different between patients with good and poor prognosis (40+/-9.39 vs. 84.25+/-26, Mann-Whitney U-test P=.014). A direct correlation of S/O ratios with PAS scores was found (Spearman r=.72, P=.028).
Conclusions: Striatal D2R density in naive schizophrenic patients may be related to DSM-IV prognostic factors and premorbid adjustment criteria (PAS). If these preliminary results are confirmed, striatal D2R density might predict premorbid and clinical features associated with poor prognosis in neuroleptic-naive patients.