Defensive Mobilization in Specific Phobia: Fear Specificity, Negative Affectivity, and Diagnostic Prominence

Abstract

Background Understanding of exaggerated responsivity in specific phobia—its physiology and neural mediators—has advanced considerably. However, despite strong phenotypic evidence that prominence of specific phobia relative to co-occurring conditions (i.e., principal versus non-principal disorder) is associated with dramatic differences in subjective distress, there is yet no consideration of such comorbidity issues on objective defensive reactivity. Methods A community sample of specific phobia (N=74 principal phobia; N=86 non-principal phobia) and control (n=76) participants imagined threatening and neutral events while acoustic startle probes were presented and eye-blink responses (orbicularis occuli) recorded. Changes in heart rate, skin conductance level, and facial expressivity were also measured. Results Principal specific phobia patients far exceeded controls in startle reflex and autonomic reactivity during imagery of idiographic fear scenes. Distinguishing between single and multiple phobias within principal phobia and comparing these to non-principal phobia revealed a continuum of decreasing defensive mobilization: single phobia patients were strongly reactive, multiple phobia intermediate, and non-principal patients reliably attenuated—the inverse of measures of pervasive anxiety and dysphoria (i.e., negative affectivity). Further, as more disorders supplanted specific phobia from principal disorder, overall defensive mobilization was systematically more impaired. Conclusions The exaggerated responsivity considered characteristic of specific phobia is limited to those patients for whom circumscribed fear is the most impairing condition, and coincident with little additional affective psychopathology. As specific phobia is superseded in severity by broad and chronic negative affectivity, defensive reactivity progressively diminishes. Focal fears may still be clinically-significant, but not reflected in objective measures of defensive mobilization.

Context and explicit threat cue modulation of the startle reflex: Preliminary evidence of distinctions between adolescents with principal fear disorders versus distress disorders

“…Given that prior reviews of neurophysiological data suggest there may be some distinctions between (a) phobic and fear disorders, (b) non-phobic anxiety disorders and negative affect, and (c) depressive disorders (see Vaidyanathan et al, 2012), larger studies that can separate these diagnostic categories will be important for informing structural models of internalizing psychopathology (e.g., Watson and Clarke, 2006; Lahey et al, 2008; Seeley et al, 2011), as well as current initiatives, such as the RDoC, which aim to redefine the classification of emotional disorders along neurobiological lines (e.g., Insel and Cuthbert, 2009; Vaidyanathan et al, 2009; Craske, 2012). In contrast to studies of anxious adults (McTeague et al, 2012) but similar to studies with anxious children (Waters et al, 2014b), the present study did not find significant differences in the number of diagnoses or self-report symptom severity between the fear and distress disorder groups. These differences could reflect on developmental differences in the capacity to report on ones’ own problems as well as the actual severity and impairment associated with emotional disorders that increases with advancing age.…”

“…Several studies have reported that individuals diagnosed with phobias (e.g., animal phobias; non-generalized social phobia), or with high levels of phobic symptoms or trait fearfulness, demonstrate greater SR magnitudes during aversive picture-viewing or imagery while showing relatively normal baseline SR magnitudes (de Jong et al, 1991; Vrana et al, 1992; Globisch et al, 1999; Cuthbert et al, 2003; Lang et al, 2007; McTeague et al 2009; 2012; Vaidyanathan et al, 2009a). Inconsistent results have been found for panic disorder (Grillon et al, 1994; Vaidyanathan et al, 2009b; McTeague et al, 2011) and generalised social phobia (McTeague et al, 2009), suggesting they may be characterised by more generalised SR activation similar to the broader and more chronic anxiety disorders discussed below.…”

“…Differences in findings may be due to variation in methodology. Blunting in depression has been obtained during viewing of pictures and films, or emotional imagery (Allen et al, 1999; Taylor-Clift et al, 2011; McTeague et al, 2012) or in anticipation of aversive tones (Waters et al, 2014a). Thus, threat is mild, imaginary, and/or may lack personal relevance (Grillon et al, 2013).…”

Affective modulation of the startle response among children at high and low risk for anxiety disorders

“…For example, 39.1% of children with anxiety disorders had diagnoses of specific phobia, which may be associated with heightened startle responses only in the context of the feared stimulus (McTeague, Lang, Wangelin, Laplante, & Bradley, 2012). …”

The Power of Theory, Research Design, and Transdisciplinary Integration in Moving Psychopathology Forward

“…Allen, Trinder, & Brennan, 1999), or have high levels of anhedonia (Kaviani et al, 2004). Similarly, in experiments by Lang and colleagues, where subjects are startled in the context of imagined scenes rather than pictures, depressed individuals show a smaller FPS than non-depressed subjects (McTeague et al, 2010; McTeague et al, 2009; McTeague, Lang, Wangelin, Laplante, & Bradley, 2012). Those with a greater number of recurrent episodes also have a smaller FPS than those with just single episodes of depression or those without depression.…”