Analysis of correlation between brain perfusion and suicidal ideation among patients with major depressive disorder

Objectives: Depression accounts for most of affective disorders, the cause of major suicide, and assessment of the degree of suicidal impulses in depressed patients is subjectively done through questionnaires. It is well known that there is a correlation between symptoms and brain perfusion in many neuropsychiatric diseases. Brain perfusion imaging can be used as an objective examination to show the extent of suicidal ideation. In this study, we aimed to see correlations between suicidal ideation and cerebral blood flow alterations in patients with major depressive disorder.

Methods: Forty-eight ​​patients diagnosed with major depressive disorder in the department of psychiatry were enrolled in this study. (male: 42, female: 6, age: 44 ± 19.03). Patients with comorbidity of other neurological illnesses, loss of consciousness due to trauma, and history of substance abuse/dependence were excluded. Tc-99m HMPAO cerebral perfusion SPECT was performed, and the results were analyzed using SPM (SPM 8, Matlab 7.6). Beck's depression inventory (BDI) was used as an assessment tool for suicide impulse scale. The question on BDI related to suicidal ideation is as follows. A score of 0 is “I don’t have any thoughts of killing myself.", and a score of 1 is "I have thoughts of killing myself but I would not carry them out.” 2 points is for “I would like to kill myself." and 3 points "I would kill myself if I had the chance." Based on this, it was divided into 3 groups (0-1 point: low-risk group, 2 point: moderate-risk group, 3 points: high-risk group). Thirteen were in the low-risk group, 25 in the moderate-risk group, and 10 in the high-risk group. First, the difference in cerebral blood flow between the three groups was compared and analyzed. Next, we examined the correlation of blood flow by BDI score for all patients.

Results: Compared with the low-risk group (n = 13), cerebral blood flow decreased in the posterior cingulate among the moderate-risk group (n = 25), (p<0.05). In the high-risk group (n = 10), cerebral blood flow decreased in Lt frontal lobe, parahippocampal gyrus and posterior cingulate compared to the low risk group (p <0.05). There was statistically significant correlation between decreasing cerebral blood flow in Lt frontal lobe, parahippocampal gyrus and posterior cingulate area as the BDI score increased in all patients (p <0.005).

Conclusion: There was a significant correlation between the severity of suicidal ideation and cerebral blood flow in patients with depression. The analysis of cerebral blood flow using cerebral perfusion SPECT could be an indicator for the objective evaluation of the degree of suicidal tendency. Research Support: