Voxel-based magnetic resonance imaging investigation of poor and preserved clinical insight in people with schizophrenia

AIM To define regional grey-matter abnormalities in schizophrenia patients with poor insight(Insight-),relative to patients with preserved clinical insight(Insight+),and healthy controls.METHODS Forty stable schizophrenia outpatients(20 Insight-and 20 Insight+) and 20 healthy controls underwent whole brain magnetic resonance imaging(MRI).Insight in all patients was assessed using the Birchwood Insight Scale(BIS;a self-report measure).The two patient groups were preselected to match on most clinical and demographic parameters but,by design,they had markedly distinct BIS scores.Voxel-based morphometry employed in SPM8 was used to examine group differences in grey matter volumes across the whole brain.RESULTS The three participant groups were comparable in age [F(2,57) = 0.34,P = 0.71] and the patient groups did not differ in age at illness onset [t(38) = 0.87,P = 0.39].Insight-and Insight+ patient groups also did not differ in symptoms on the Positive and Negative Syndromes scale(PANSS):Positive symptoms [t(38) = 0.58,P = 0.57],negative symptoms [t(38) = 0.61,P = 0.55],general psychopathology [t(38) = 1.30,P = 0.20] and total PANSS scores [t(38) = 0.21,P = 0.84].The two patient groups,as expected,varied significantly in the level of BIS-assessed insight [t(38) = 12.11,P < 0.001].MRI results revealed lower fronto-temporal,parahippocampal,occipital and cerebellar grey matter volumes in Insightpatients,relative to Insight+ patients and healthy controls(for all clusters,family-wise error corrected P < 0.05).Insight+ patient and healthy controls did not differ significantly(P > 0.20) from each other.CONCLUSION Our findings demonstrate a clear association between poor clinical insight and smaller fronto-temporal,occipital and cerebellar grey matter volumes in stable long-term schizophrenia patients.