title: The temptation of suicide: striatal gray matter, discounting of delayed rewards, and suicide attempts in late-life depression.
abstract: BACKGROUND
  Converging evidence implicates basal ganglia alterations in impulsivity and suicidal behavior. For example, D2/D3 agonists and subthalamic nucleus stimulation in Parkinson's disease (PD) trigger impulse control disorders and possibly suicidal behavior. Furthermore, suicidal behavior has been associated with structural basal ganglia abnormalities. Finally, low-lethality, unplanned suicide attempts are associated with increased discounting of delayed rewards, a behavior dependent upon the striatum. Thus, we tested whether, in late-life depression, changes in the basal ganglia were associated with suicide attempts and with increased delay discounting.
  
  
  METHODS
  Fifty-two persons aged ≥ 60 years underwent extensive clinical and cognitive characterization: 33 with major depression [13 suicide attempters (SA), 20 non-suicidal depressed elderly] and 19 non-depressed controls. Participants had high-resolution T1-weighted magnetization prepared rapid acquisition gradient-echo (MPRAGE) magnetic resonance imaging (MRI) scans. Basal ganglia gray matter voxel counts were estimated using atlas-based segmentation, with a highly deformable automated algorithm. Discounting of delayed rewards was assessed using the Monetary Choice Questionnaire (MCQ) and delay aversion with the Cambridge Gamble Task (CGT).
  
  
  RESULTS
  SA had lower putamen but not caudate or pallidum gray matter voxel counts, compared to the control groups. This difference persisted after accounting for substance use disorders and possible brain injury from suicide attempts. SA with lower putamen gray matter voxel counts displayed higher delay discounting but not delay aversion. Secondary analyses revealed that SA had lower voxel counts in associative and ventral but not sensorimotor striatum.
  
  
  CONCLUSIONS
  Our findings, although limited by small sample size and the case-control design, suggest that striatal lesions could contribute to suicidal behavior by increasing impulsivity.
authors: Western Psychiatric Institute and Clinic, Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA PA 15213, USA. dombrovskia@upmc.edu
authors: A Y
authors: AY
authors: Dombrovski
authors: G J
authors: GJ
authors: Siegle
authors: K
authors: K
authors: Szanto
authors: L
authors: L
authors: Clark
authors: C F
authors: CF
authors: Reynolds
authors: H
authors: H
authors: Aizenstein
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001479:Basal Ganglia / Q000473:pathology*; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000175:diagnosis; D003657:Decision Making / Q000502:physiology; D003865:Major Depressive Disorder / Q000473:pathology* / Q000523:psychology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007175:Impulsive Behavior / Q000473:pathology* / Q000523:psychology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011699:Putamen / Q000473:pathology; D012201:Reward; D012720:Severity of Illness Index; D013406:Suicide, Attempted / Q000523:psychology*