Individuals with current suicidal ideation demonstrate implicit "fearlessness of death".

BACKGROUND AND OBJECTIVES: Suicidal behaviour has proved to be difficult to predict, due in part to the particular limitations of introspection within suicidality. In an effort to overcome this, recent research has demonstrated the utility of indirect measures of "implicit" attitudes within the study of suicidality. However, research to date has focused predominantly on implicit self-evaluations and self-death associations. No work has examined implicit evaluations of death, despite the theoretical importance of such evaluations; "fearlessness of death" is central to both the Interpersonal Theory of Suicide and the Integrated Motivational-Volitional model of suicide.. METHODS: Twenty-three psychiatric patients with current suicidal ideation and twenty-five normative university students completed two versions of the Implicit Relational Assessment Procedure (IRAP) that targeted evaluations of death. One task specified personal death (i.e., was self-focused) and the other targeted death in the abstract. RESULTS: Self-focused evaluations of death reliably distinguished between the two groups, correctly classifying 74% of cases, but evaluations of death in the abstract did not. The suicidal group produced specific biases indicating a rejection of the negativity of death. Results are consistent with the definition of suicidality as involving a self-focused wish to die.. LIMITATIONS: For ethical reason, suicidal behaviours were not assessed in the normative group. Groups were therefore not mutually exclusive. This may have decreased the specificity of the IRAP. CONCLUSIONS: Suicidal ideation is associated with an implicit "fearlessness of death". The utility of implicit death-evaluations should therefore be considered alongside self-evaluations and self-death associations in the future..

Event-related brain potentials reveal correlates of the transformation of stimulus functions through derived relations in healthy humans.

This research aimed to explore the neural correlates of relational learning by recording high-density EEG during a behavioural task involving derivation levels of varying complexity. A total of 15 participants (5 male; age range 18-23 years; mean age=20.0 years) completed contextual cue training, relational learning, function training and a derivation task while 128-channel event-related potentials (ERPs) were recorded from the scalp (Background). Differences in response latencies were observed between the two derived (symmetry and equivalence) and directly trained relations, with longest latencies found for equivalence and shortest for the directly trained relations. This pattern failed to reach statistical significance. Importantly, ERPs revealed an early P3a positivity (from 230 to 350ms) over right posterior scalp sites. Significantly larger mean amplitudes were found at three channels (P6, E115 and E121) for the equivalence relations compared to the two other types (Results). We believe this may constitute a first demonstration of differences in brain electrophysiology in the transformation of stimulus functions through derived relations of hierarchical levels of complexity (Conclusions).