Decision-making Competence and Attempted Suicide

Published in: The Journal of Clinical Psychiatry, v. 76, no. 12, Dec. 2015, p. e1590-e1597

Posted on RAND.org on April 28, 2016

by Katalin Szanto, Wandi Bruine de Bruin, Andrew M. Parker, Michael N. Hallquist, Polina M. Vanyukov, Alexandre Y. Dombrovski

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Research Question

  1. Are decision-making biases more common among people who attempt suicide?

OBJECTIVE: The propensity of people vulnerable to suicide to make poor life decisions is increasingly well documented. Do they display an extreme degree of decision biases? The present study used a behavioral-decision approach to examine the susceptibility of low-lethality and high-lethality suicide attempters to common decision biases that may ultimately obscure alternative solutions and deterrents to suicide in a crisis. METHOD: We assessed older and middle-aged (42–97 years) individuals who made high-lethality (medically serious) (n = 31) and low-lethality suicide attempts (n = 29). Comparison groups included suicide ideators (n = 30), nonsuicidal depressed participants (n = 53), and psychiatrically healthy participants (n = 28). Attempters, ideators, and nonsuicidal depressed participants had nonpsychotic major depression (DSM-IV criteria). Decision biases included sunk cost (inability to abort an action for which costs are irrecoverable), framing (responding to superficial features of how a problem is presented), underconfidence/overconfidence (appropriateness of confidence in knowledge), and inconsistent risk perception. Data were collected between June 2010 and February 2014. RESULTS: Both high- and low-lethality attempters were more susceptible to framing effects as compared to the other groups included in this study (P ≤ .05, ηp2 = 0.06). In contrast, low-lethality attempters were more susceptible to sunk costs than both the comparison groups and high-lethality attempters (P ≤ .01, ηp2 = 0.09). These group differences remained after accounting for age, global cognitive performance, and impulsive traits. Premorbid IQ partially explained group differences in framing effects. CONCLUSIONS: Suicide attempters' failure to resist framing may reflect their inability to consider a decision from an objective standpoint in a crisis. Failure of low-lethality attempters to resist sunk cost may reflect their tendency to confuse past and future costs of their behavior, lowering their threshold for acting on suicidal thoughts.

Key Findings

  • Suicide attempters were less likely than other control groups to be able to sidestep two cognitive biases (errors in thinking that affect decisions and judgments): framing effects and sunk cost bias.
  • Both low- and high-lethality attempters were susceptible to framing effects, meaning that their choices changed with irrelevant wording changes.
  • Those who used low-lethality methods were prone to sunk cost bias, meaning they were less likely to walk away from a situation in which resources (time, effort, money) had been invested and could not be recovered.
  • A goal for psychotherapy with suicide attempters could involve improved decision-making skills.

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