title: Neural correlates of suicidal ideation and its reduction in depression.
abstract: BACKGROUND
  The neural correlates of suicidal ideation and its reduction after treatment are unknown. We hypothesized that increased regional cerebral glucose metabolism in the infralimbic cortex (Brodmann area 25), amygdala, and subgenual anterior cingulate cortex would be associated with suicidal ideation and its reduction after ketamine infusion.
  
  
  METHODS
  Medication-free patients (n=19) with treatment-resistant major depressive disorder underwent positron emission tomography imaging at baseline and 230 minutes after an open-label ketamine infusion (0.5 mg/kg for 40 minutes).
  
  
  RESULTS
  Baseline suicidal ideation and regional cerebral glucose metabolism in the infralimbic cortex were significantly correlated (r=.59, P=.007); but not overall mood scores (r=-.07, P=.79). Reductions in suicidal ideation after ketamine infusion were correlated with decreased regional cerebral glucose metabolism in the infralimbic cortex (r=.54, P=.02). Metabolism in other areas of interest was not significantly correlated with suicidal ideation or depression.
  
  
  CONCLUSIONS
  The infralimbic cortex may be implicated in suicidal ideation.
authors.affiliation: Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland (Dr Ballard, Mr Lally, Dr Nugent, Dr Furey, Mr Luckenbaugh, and Dr Zarate); Institute of Cognitive Neuroscience, University College London, London, WC1N 3AR, UK (Mr Lally). elizabeth.ballard@nih.gov.
authors.forename: Elizabeth D
authors.initials: ED
authors.lastname: Ballard
authors.affiliation: Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland (Dr Ballard, Mr Lally, Dr Nugent, Dr Furey, Mr Luckenbaugh, and Dr Zarate); Institute of Cognitive Neuroscience, University College London, London, WC1N 3AR, UK (Mr Lally).
authors.forename: Níall
authors.initials: N
authors.lastname: Lally
authors.affiliation: Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland (Dr Ballard, Mr Lally, Dr Nugent, Dr Furey, Mr Luckenbaugh, and Dr Zarate); Institute of Cognitive Neuroscience, University College London, London, WC1N 3AR, UK (Mr Lally).
authors.forename: Allison C
authors.initials: AC
authors.lastname: Nugent
authors.affiliation: Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland (Dr Ballard, Mr Lally, Dr Nugent, Dr Furey, Mr Luckenbaugh, and Dr Zarate); Institute of Cognitive Neuroscience, University College London, London, WC1N 3AR, UK (Mr Lally).
authors.forename: Maura L
authors.initials: ML
authors.lastname: Furey
authors.affiliation: Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland (Dr Ballard, Mr Lally, Dr Nugent, Dr Furey, Mr Luckenbaugh, and Dr Zarate); Institute of Cognitive Neuroscience, University College London, London, WC1N 3AR, UK (Mr Lally).
authors.forename: David A
authors.initials: DA
authors.lastname: Luckenbaugh
authors.affiliation: Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland (Dr Ballard, Mr Lally, Dr Nugent, Dr Furey, Mr Luckenbaugh, and Dr Zarate); Institute of Cognitive Neuroscience, University College London, London, WC1N 3AR, UK (Mr Lally).
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Zarate
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001931:Brain Mapping; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D061218:Depressive Disorder, Treatment-Resistant / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007649:Ketamine / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011569:Psychiatric Status Rating Scales; D059020:Suicidal Ideation; D016896:Treatment Outcome
chemical_list: D007649:Ketamine; D005947:Glucose
keywords: PET imaging; depression; ketamine; suicidal ideation