Psychoneurometric operationalization of threat sensitivity: Relations with clinical symptom and physiological response criteria

Abstract

The National Institute of Mental Health's Research Domain Criteria (RDoC) initiative calls for the incorporation of neurobiological approaches and findings into conceptions of mental health problems through a focus on biobehavioral constructs investigated across multiple domains of measurement (units of analysis). Although the constructs in the RDoC system are characterized in "process terms" (i.e., as functional concepts with brain and behavioral referents), these constructs can also be framed as dispositions (i.e., as dimensions of variation in biobehavioral functioning across individuals). Focusing on one key RDoC construct, acute threat or "fear," the current article illustrates a construct-oriented psychoneurometric strategy for operationalizing this construct in individual difference terms-as threat sensitivity (THT+). Utilizing data from 454 adult participants, we demonstrate empirically that (a) a scale measure of THT+ designed to tap general fear/fearlessness predicts effectively to relevant clinical problems (i.e., fear disorder symptoms), (b) this scale measure shows reliable associations with physiological indices of acute reactivity to aversive visual stimuli, and (c) a cross-domain factor reflecting the intersection of scale and physiological indicators of THT+ predicts effectively to both clinical and neurophysiological criterion measures. Results illustrate how the psychoneurometric approach can be used to create a dimensional index of a biobehavioral trait construct, in this case THT+, which can serve as a bridge between phenomena in domains of psychopathology and neurobiology. Implications and future directions are discussed with reference to the RDoC initiative and existing report-based conceptions of psychological traits.

Keywords: Individual differences; Other; Psychopathology.

Figure 1

Scree plot and variable loadings for factor analysis (N = 454) of TF-55 scores, corrugator EMG differentiation (aversive-neutral), heart rate acceleration (aversive), and startle blink potentiation (aversive-neutral). A one-factor solution is evident both by visual inspection of the scree plot and by parallel analysis, a technique for determining the number of factors to retain by comparing the eigenvalues of the sample data with those of randomly generated data (Horn, 1965). Actual eigenvalues are denoted in the plot by a solid line; eigenvalues estimated from a parallel analysis based on 1000 random samples are denoted by a dashed line.

Figure 2

Depiction of convergent and discriminant correlations (N = 454) for three predictor variables, where bar amplitudes reflect r values: Blue bars = threat sensitivity (THT+) as indexed by TF-55 scale scores; red bars = THT+ as indexed by physiology-only factor scores (indicators = corrugator differentiation, aversive HR acceleration, and startle potentiation); purple bars = THT+ as indexed by psychoneurometric factor scores (indicators = TF-55, corrugator, HR, startle). Left and middle-left sets of bars reflect convergent rs with conceptually-relevant criterion measures, consisting of scores on (a) a composite of fear disorder symptoms (social phobia, specific phobia, panic disorder, agoraphobia), and (c) a composite of other physiological THT+ indicators (aversive-neutral difference scores for LPP, Probe P3, and orbicularis EMG; general corrugator muscle tension). Middle-right and right sets of bars reflect discriminant rs with conceptually-irrelevant criterion measures, consisting of scores on (a) a composite of substance use disorder symptoms (alcohol abuse and dependence; drug abuse and dependence), and (b) amplitude of P3 brain response to target stimuli within a visual oddball task.

Figure 3

Conceptual-empirical depiction of results from analyses aimed at operationalizing a psychoneurometric index of threat sensitivity. The lower part of the figure depicts relations among observables across domains of self-report (scale, clinical symptom) and physiological response. Factor loadings of scale (dark blue square) and physiological (dark red squares) observables on the latent psychoneurometric factor are denoted by dashed arrows. Light blue and red squares represent composite scores for clinical (fear disorder) symptom criteria and physiological response criteria, respectively. Correlation coefficients between criterion composites and scores on the latent psychoneurometric factor (purple oval) are depicted by bidirectional arrows. The upper part of the figure depicts how the psychoneurometric approach can systematically shift the conceptualization of threat sensitivity from a construct rooted in self-report (light blue cloud) toward one that reflects the nexus of psychological and biological processes (light purple cloud). This process of bootstrapping (Cronbach & Meehl, 1955) is depicted by the light blue and light purple arrows.