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, which may ultimately obscure alternative solutions and deterrents to suicide in a crisis. Method: We assessed older and middle-aged individuals who made high-lethality (medically serious; N=31) and low-lethality suicide attempts (N=29). Comparison groups included suicide ideators (N=30), non-suicidal depressed (N=53), and psychiatrically healthy participants (N=28). Attempters, ideators, and non-suicidal depressed participants had unipolar non-psychotic major depression. 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), under/overconfidence (appropriateness of confidence in knowledge), and inconsistent risk perception. Data were collected between June of 2010 and February of 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< 0.05, ηp2 =.06). In contrast, low-lethality attempters were more susceptible to sunk costs than both the comparison groups and high-lethality attempters (p< 0.01, ηp2 =.09). These group differences remained after accounting for age, global cognitive performance, and impulsive traits. Premorbid IQ partially explained group differences in framing effects. Conclusion: Suicide attempters’ failure to resist framing may reflect their inability to consider a decision from an objective standpoint in a crisis. Low-lethality attempters’ failure 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

Evidence of causal effect of major depression on alcohol dependence: findings from the psychiatric genomics consortium

BACKGROUND Despite established clinical associations among major depression (MD), alcohol dependence (AD), and alcohol consumption (AC), the nature of the causal relationship between them is not completely understood. We leveraged genome-wide data from the Psychiatric Genomics Consortium (PGC) and UK Biobank to test for the presence of shared genetic mechanisms and causal relationships among MD, AD, and AC. METHODS Linkage disequilibrium score regression and Mendelian randomization (MR) were performed using genome-wide data from the PGC (MD: 135 458 cases and 344 901 controls; AD: 10 206 cases and 28 480 controls) and UK Biobank (AC-frequency: 438 308 individuals; AC-quantity: 307 098 individuals). RESULTS Positive genetic correlation was observed between MD and AD (rgMD−AD = + 0.47, P = 6.6 × 10−10). AC-quantity showed positive genetic correlation with both AD (rgAD−AC quantity = + 0.75, P = 1.8 × 10−14) and MD (rgMD−AC quantity = + 0.14, P = 2.9 × 10−7), while there was negative correlation of AC-frequency with MD (rgMD−AC frequency = −0.17, P = 1.5 × 10−10) and a non-significant result with AD. MR analyses confirmed the presence of pleiotropy among these four traits. However, the MD-AD results reflect a mediated-pleiotropy mechanism (i.e. causal relationship) with an effect of MD on AD (beta = 0.28, P = 1.29 × 10−6). There was no evidence for reverse causation. CONCLUSION This study supports a causal role for genetic liability of MD on AD based on genetic datasets including thousands of individuals. Understanding mechanisms underlying MD-AD comorbidity addresses important public health concerns and has the potential to facilitate prevention and intervention efforts

Eye movement control during learning and scanning of Landolt-C stimuli: Exposure frequency effects and spacing effects in a visual search task.

We examined whether typical frequency effects observed in normal reading would also occur in a target search task using non-linguistic Landolt-C stimuli. In an initial learning session, we simulated development of frequency effects by controlling exposures participants received of Landolt-C clusters during learning. In a subsequent scanning session, we manipulated the cluster demarcation form of linear strings of Landolt-C clusters (i.e., spaced vs. unspaced vs. shaded unspaced). Participants were required to scan and search for pre-learnt target clusters that were embedded in longer Landolt-C strings. During learning, frequency effects were successfully simulated such that targets with more exposures received shorter fixation time than those with fewer exposures. Participants were unable to successfully detect the pre-learnt targets when they were embedded in the strings during scanning. No evidence of frequency effects was observed in the scanning session. In contrast, eye movement control was significantly influenced by cluster demarcation form, with increased difficulty for unspaced strings, less for shaded strings and least for spaced strings. Furthermore, typical landing position distributions that occur in reading of spaced languages also occurred during scanning of spaced Landolt-C strings but not for the shaded, nor the unspaced strings. In conclusion, exposure frequency effects were successfully simulated during learning but did not carry over to target search during scanning of Landolt-C strings. Possible reasons why frequency effects did not occur in the scanning session are discussed