4 - (Sym 102) Reinforcement-based Behavioral Adaptation in Attempted Suicide

Research suggests that vulnerability to suicidal behavior (SB) involves trait-like disruptions in value-based decision-making, including choice processes and reward learning. At the same time, prior studies have largely relied on the paradigms that do not take into consideration the  complexity of real-world dynamic environments and learning in the context of such environments. This hinders our understanding of the ways in which the multi-faceted real-world demands on decision-making, such as those imposed by a suicidal crisis, exacerbate the previously identified trait-like alterations. In this study, we sought to capture real-time evolution of decision processes through the use of a reinforcement-based timing paradigm and computational modeling techniques. We expected that suicide attempters would exhibit deficits in reinforcement-based behavioral adaptation, which would be further amplified by increased information load. 

Participants were 104 individuals diagnosed with borderline personality disorder (BPD; Mean age: 30.71, SD=9.56; 83% female) and 48 healthy controls (Mean age: 31.38, SD=8.52; 73% female). Of the individuals with BPD, 75 had a history of suicide attempts (32 were high- and 43 were low-lethality attempters) and 29 reported no past suicide attempts. Participants completed six runs of the reinforcement-based timing paradigm during which they were required to explore and learn reward contingencies and thus ultimate response timing in a challenging unidimensional environment.

We found a significant Lethality Group × Last Outcome × Response Time interaction, χ²(3) = 32.36, p < 10^-7 and a significant Lethality Group × Trial Number × Convergence on the Best Response Option interaction, χ²(3) = 12.94, p = .005. Follow-up analyses revealed that, compared to all other groups, high-lethality suicide attempters displayed impaired levels of short-term reinforcement-based behavioral adaptation. In contrast, long-term reinforcement-based behavioral adaptation was impaired in all participants with BPD (compared to healthy controls) independently of a suicide attempt history.

Our findings contribute to a better understanding of value-based decision-making in SB in complex dynamic environments that approximate some of the cognitive demands of a suicidal crisis. They suggest that suicide attempters exhibit deficient adjustment to short-term reinforcement, which might relate to problem-solving and decision-making deficits that facilitate the choice of suicide over alternatives.