Suicidal ideation is associated with reduced prefrontal activation during a verbal fluency task in patients with major depressive disorder.
BACKGROUND
Despite the known relationship between prefrontal function and increased suicidality during major depressive episodes, the links between prefrontal function and suicidality remain unclear in major depressive disorder (MDD). Suicidal ideation usually precedes a suicide attempt. If prefrontal cortex (PFC) activity is a biomarker for suicidal ideation in depression, monitoring it could be useful for suicide prevention. Therefore, in this study, we assessed the association between prefrontal function and suicidal ideation in MDD.


METHODS
Prefrontal function in 67 patients with MDD (31 with suicidal ideation and 36 without) and 67 age-, gender-, and intelligence quotient-matched healthy controls (HCs) was evaluated using near-infrared spectroscopy (NIRS) during a verbal fluency task (VFT). Suicidal ideation was assessed using item 3 of the Hamilton Depression Rating Scale (HAMD).


RESULTS
Regional hemodynamic changes were significantly smaller in patients with MDD than in HCs in prefrontal and temporal regions. Hemodynamic changes in the right dorsolateral PFC (DLPFC), orbitofrontal cortex (OFC), and right frontopolar cortex (FPC) regions in patients with MDD with suicidal ideation were significantly smaller than in those without suicidal ideation. In addition, hemodynamic changes correlated negatively with the severity of suicidal ideation in the DLPFC, OFC, and FPC in patients with MDD.


CONCLUSIONS
Further studies with a larger sample size are required to verify our findings.


CONCLUSIONS
These results suggest that the DLPFC, OFC, and FPC are brain substrates of suicidal ideation in depressive states in patients with MDD, and that NIRS data can be employed as a clinically useful biomarker for the assessment of suicide risk.
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan. Electronic address: pshh0517@yahoo.co.jp.
Shenghong
S
Pu
National Center of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8551, Japan.
Kazuyuki
K
Nakagome
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Takeshi
T
Yamada
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Katsutoshi
K
Yokoyama
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Hiroshi
H
Matsumura
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Sayaka
S
Yamada
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Takuya
T
Sugie
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Akihiko
A
Miura
Division of Technical Support, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Hideaki
H
Mitani
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Masaaki
M
Iwata
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Izumi
I
Nagata
Division of Neuropsychiatry, Department of Brain and Neuroscience, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
Koichi
K
Kaneko
D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000503:physiopathology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D059907:Functional Neuroimaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000503:physiopathology*; D019265:Spectroscopy, Near-Infrared; D059020:Suicidal Ideation; D013702:Temporal Lobe / Q000503:physiopathology; D014705:Verbal Behavior / Q000502:physiology*
Major depressive disorder; Near-infrared spectroscopy; Prefrontal cortex; Suicidal ideation; Verbal fluency task