Prefrontal cortex, temporal cortex, and hippocampus volume are affected in suicidal psychiatric patients

Abstract

Suicide is a leading cause of death in America, with over 40,000 reported suicides per year. Mental illness is a major risk factor for suicidality. This study attempts to validate findings of volumetric differences from studies on suicidality. Psychiatric inpatients classified as having mildly severe or severe depression were separated into two groups: suicide attempted in the past two months (SA; n=20), non-suicidal control group (DA; n=20); these patients were all depressed and not significantly different for age, gender, race, marital status, education level, anxiety level, and substance abuse. Healthy controls (HC; n=20) were not significantly different from the suicidal groups for age and gender. Volunteers underwent MRI to assess volumes of cortical lobes, corpus callosum, and subcortical regions of interest, including the thalamus, insula, limbic structures, and basal ganglia. The right hippocampal volume of the SA group was significantly reduced compared to healthy controls. The frontal and temporal lobe volumes of the SA group were significantly decreased compared to the DA group. These volumetric reductions confirm previous findings and support the hypothesis that fronto-temporal function may be altered in suicidal patients.

Keywords: Freesurfer; Frontal lobe; Hippocampus; Replication; Suicide; Temporal lobe.

Fig. 1.

Group Differences in Cortical and Subcortical Regions of Interest. Significant results from univariate F tests derived from the multiple analyses of covariance comparing SA vs. DA and SA vs. HC. Error bars represent standard deviation.

Fig. 2.

Group Differences in Frontal Regions of Interest. Results of the univariate F tests performed on the regions subdivided from the left and right frontal cortex. DA: depressed controls compared to suicidal attempt group; SA: suicidal attempt group. Regions were obtained from the Desikan-Kiliany Atlas in Freesurfer. Significance was set at p < 0.05. Covariates used for the MANCOVA were age, gender, marital status, total brain volume, anxiety level, depression severity and total substance use. Error bars represent standard deviations. Significant findings include right precentral gyrus (p < 0.05), right pars triangularis (p < 0.05), right caudal middle frontal gyrus (p < 0.05), left precentral gyrus (p < 0.010), and left paracentral lobule (p < 0.05) volumes.

Fig. 3.

Group Differences in Temporal Regions of Interest. Result of the univariate F tests performed on the regions subdivided from the left and right temporal cortex. DA: depressed controls compared to suicidal attempt group; SA: suicidal attempt group Regions were obtained from the Desikan-Kiliany Atlas in Freesurfer. Significance was set at p < 0.05. Covariates used for the MANCOVA were age, gender, marital status, total brain volume, anxiety level, depression severity and total substance use. Error bars represent standard deviations.