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

Abstract

AIMTo define regional grey-matter abnormalities in schizophrenia patients with poor insight (Insight-), relative to patients with preserved clinical insight (Insight+), and healthy controls.METHODSForty 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 pre-selected 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.RESULTSThe 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 Insight- patients, 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.CONCLUSIONOur 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.

Insight in schizophrenia spectrum disorders: relationship with behavior, mood and perceived quality of life, underlying causes and emerging treatments

“…Structural neuroimaging studies have linked poor insight to reduced volume in several areas, including frontal 104,106,107 , temporal 107,108 , parietal 104,107 and occipital 107 regions, the thalamus 101 , basal ganglia 104 and cerebellum 107 , in both first-episode psychosis 109 and chronic schizophrenia 107 .…”

“…Reduced cortical thickness has been observed in those with poorer insight in the superior temporal gyrus, parahippocampus and insula 107 as well as in the ventral lateral prefrontal cortex in schizophrenia, and in other frontal, parietal and temporal areas in first-episode psychosis 110 . Structural changes in white matter integrity, suggesting impaired connectivity, have also been found in chronic 111 and early phase psychosis 100,112 .…”

The right occipital lobe and poor insight in first-episode psychosis

“…However, most of the studies addressing insight in non-affective psychosis compared patients in the chronic phase of schizophrenia with healthy volunteers, which might have introduced the effect of the illness as a confounding factor. For example, a recent study found that schizophrenia patients with poor insight had widespread reductions in GMV as compared to those with preserved insight [ 52 ] but this may have been confounded by long-term exposure to neuroleptic drugs[ 53 ]. In addition, many of the previous studies adopted a region of interest approach rather than the less constrained whole brain approach.…”

“…The role of medial temporal gyrus in insight deserves comment. Previous studies have shown reductions in this area in patients with poor insight[ 52 ] or have correlated its volume with insight in patients with schizophrenia[ 20 , 22 ]. This part of the temporal lobe has been classically associated with semantic and memory processing [ 58 ], and multimodal sensory integration [ 59 ].…”

Decreases in retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness in schizophrenia, relation to insight: a controlled study

“…26 İç görüsüz şizofreni hastalarında yapılan görüntüleme çalışmaların-da, MSS'de yaygın nöronal dejenerasyon, sağ insulada kortikal incelme, temporal ve parietal gri madde hacminde azalma, frontotemporal beyaz cevher hacminde azalma, prefrontal, temporal ve serebellar nörodejenerasyonların olduğu bildirilmiştir. [26][27][28][29][30] İç görüsüzlüğün kliniğe olan olumsuz etkileri nedeniyle MSS düzeneklerinin anlaşılması önemlidir. 31 Bildiğimiz kadarı ile literatürde şizofreni hastalarında GHIP tabakasını inceleyen sadece bir çalışma varken, iç görüsüz şizofreni hastalarında retina kalınlığını inceleyen çalışma yoktur.…”