Decision-making competence and attempted 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.