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Implicit Cognitions
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Suicide or Life-Death Implicit
Association Task (S/LD-IAT) |
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Stronger self-death/suicide association among those with a prior suicide attempt compared to those with no attempt history (Barnes et al., 2017; Glenn et al., 2017; Nock et al., 2010). Death/suicide self-associations prospectively predict future suicide attempt (Barnes et al., 2017; Ellis et al., 2016; Glenn et al., 2017; Nock & Banaji, 2007; Nock et al., 2010; Tello et al., 2020). Some studies show limited long-term predictive capacity of the S/LD-IAT (Harrison et al., 2018; Rath et al., 2021). In healthy volunteers with no suicide history, self-death associations are linked to greater activation of the insula (Ballard et al., 2019) and enhanced gamma oscillations in the amygdala and anterior insula (Ballard, Gilbert et al., 2020).
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Attentional Biases
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| Suicide Stroop Task |
Measures attentional fixation on suicide-related semantic cues by assessing response latencies when naming the font color of words that represent suicide compared to negatively valanced or neutral words. Greater response latencies (i.e., slower reaction times) reflect a diminished ability to disengage from suicide- relevant stimuli. Assesses attentional allocation to neutral, negative, or positive emotionally valanced stimuli via response latencies to words, images, or faces. Faster response times for congruent trials (i.e., when the probe and emotional stimulus are paired) indicate an attentional bias toward emotional as opposed to neutral stimuli.
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Greater response latencies to suicide-related words in those with prior suicide attempts (Becker et al., 1999; Stewart et al., 2017; Tavakoli et al., 2021; Williams & Broadbent, 1986), particularly those with recent attempts (Cha et al., 2010). Some have reported concerns surrounding this task’s ability to characterize suicide risk; for instance, the effect sizes are small (Richard-Devantoy et al., 2016a), the task performs close to chance in differentiating attempters from non-attempters (Wilson et al., 2019), and it might not outperform traditional self-report measures in characterizing risk (Chung & Jeglic, 2016). Neural responses to angry faces differentiated suicide attempters from non-suicidal controls in several regions of the prefrontal cortex (Jollant et al., 2008). Among attempters, an increase in the positive association between theta power and suicide ideation was observed for angry versus happy faces in the extended amygdala-hippocampal region; the opposite pattern was found in non-attempters (Gilbert et al., 2022). No behavioral effects emerged in this task (Gilbert et al., 2022). Suicide ideators are more sensitive to negatively valanced stimuli than to positively valanced stimuli, as indexed by larger N1 amplitudes to fearful and sad faces (Lin et al., 2022).
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| Dot Probe Task |
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Response Inhibition and Impulsivity
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| Go/No-Go Task |
Measures inhibition of prepotent responses through participants’ ability to respond to a designated target on a screen (Go trials) and to inhibit responding to an intermittent non-target (No-Go trials). Measures the propensity to devalue temporally distant rewards as an index of impulsive decision-making. Greater discounting is a reflection of immediate versus delayed gratification.
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Higher false alarm rates in attempters (i.e., failure to inhibit responding to a No-Go target) (Richard-Devantoy et al., 2012, 2016b; Westheide et al., 2008). Task performance differentiated impulsive attempters from both non-impulsive attempters and non-attempters (Wojnar et al., 2009). Self-reported impulsiveness did not differentiate these groups (Wojnar et al., 2009). Increased Go/No-Go miss rates (i.e., a failure to respond to a Go target) predicted subsequent attempts among those with severe ideation and past year attempts (Myers et al., 2022). Past-week attempts were associated with greater commission errors on the Go/No-Go task compared to more distal attempts (>1 year prior) (Interian et al., 2020). Prior suicide attempts linked to high delay discounting (Bryan & Bryan, 2021; Dombrovski et al., 2011; Liu et al., 2012; Mathias et al., 2011), with exceptions (e.g., Bridge et al., 2015). Greater delay discounting is associated with low-lethality suicide attempts whereas low delay discounting is associated with high-lethality and planned suicide attempts (Dombrovski et al., 2011).
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| Delay Discounting Task |
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Interpersonal Difficulties
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| Cyberball Task |
Social exclusion is manipulated using a computerized ball-toss game. Participants experience either inclusion (i.e., the ball is equally distributed between the participant and other players) or exclusion (i.e., the ball is predominantly distributed between the other players, but not the participant).
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Compared with non-suicidal clinical samples and healthy volunteers, suicide attempters showed decreased oxytocin levels during exclusion phases (Chu et al., 2020). Attempters reported no desire for emotional support following exclusion (Chu et al., 2020). Attempters showed reduced posterior insular activity during exclusion relative to non-attempters and healthy volunteers (Olié et al., 2017).
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Physiological Sensitivity
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| Pain Sensitivity Tasks |
Objectively measure pain sensitivity by administering cold water or mild electrical shocks to participants’ hands or fingers, with endurance time as the index of pain tolerance. Measures aversion via electromyographic eye blink responses to a startle probe while viewing emotionally valanced images. Potentiated eye-blink response is a proxy measure of increased aversion to these stimuli.
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Those with prior suicide attempts showed elevated pain tolerance relative to psychiatric controls and healthy volunteers (Orbach et al., 1996a,b, 1997), with exceptions (e.g., Rabasco & Andover, 2020). Compared to patients hospitalized for accident-related injuries, those hospitalized for suicide attempts had significantly higher pain tolerance to electric shocks (Orbach et al., 1996a). Perceived negative life stress was positively associated with pain tolerance in attempters, but the opposite pattern was found in accident victim and control groups (Orbach et al., 1996a). Compared to suicide ideators and those who attempted suicide only once, those with multiple attempts showed greater startle potentiation to unpleasant images (Hazlett et al., 2016). Effects were not observed in response to equally arousing pleasant images or self-reported picture valence (Hazlett et al., 2016). Attempters did not differ from suicide ideators or healthy volunteers in psychophysiological reactivity to suicide-specific images (Smith et al., 2010). Elevated startle potentiation to predictable threats found in depressed inpatients with a prior suicide attempt relative to depressed inpatients with no history of suicide attempt (Ballard et al., 2014).
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| Affectively Modulated Startle Reflex Task |
