Neural responsiveness to reward and suicidal ideation in social anxiety and major depression before and after psychotherapy

Abstract

Suicidality is prevalent in Social Anxiety Disorder (SAD) and Major Depressive Disorder (MDD). Limited data indicate the reward positivity (RewP), a neurophysiological index of reward responsivity, and subjective capacity for pleasure may serve as brain and behavioral assays for suicide risk though this has yet to be examined in SAD or MDD in the context of psychotherapy. Therefore, the current study tested whether suicidal ideation (SI) relates to RewP and subjective capacity for anticipatory and consummatory pleasure at baseline and whether Cognitive Behavioral Therapy (CBT) impacts these measures. Participants with SAD (n = 55) or MDD (n = 54) completed a monetary reward task (gains vs. losses) during electroencephalogram (EEG) before being randomized to CBT or supportive therapy (ST), a comparator common factors arm. EEG and SI data were collected at baseline, mid-treatment, and post-treatment; capacity for pleasure was collected at baseline and post-treatment. Baseline results showed participants with SAD or MDD were comparable in SI, RewP, and capacity for pleasure. When controlling for symptom severity, SI negatively corresponded with RewP following gains and SI positively corresponded with RewP following losses at baseline. Yet, SI did not relate to subjective capacity for pleasure. Evidence of a distinct SI-RewP association suggests RewP may serve as a transdiagnositic brain-based marker of SI. Treatment outcome revealed that among participants with SI at baseline, SI significantly decreased regardless of treatment arm; also, consummatory, but not anticipatory, pleasure increased across participants regardless of treatment arm. RewP was stable following treatment, which has been reported in other clinical trial studies.

Keywords: Depression; EEG; Reward positivity; Social anxiety; Suicidal ideation; Treatment.

Figure 1.

Response-locked ERP waveform (FCz) following gain (i.e., win), loss, and the gain minus loss difference wave (ΔRewP) for non-suicidal ideation group (n=50) (top left panel) and suicidal ideation group (n=59) (bottom left panel) at baseline; topographic scalp map of neural activity depicting the gain minus loss (ΔRewP) difference 250-350 ms after feedback presentation for non-suicidal ideation group (top right panel) and suicidal ideation group (bottom right panel) at baseline.

Figure 2.

Scatterplot illustrating relationship between suicidal ideation and FCz based on difference for gains (i.e., win) minus loss (ΔRewP) controlling for anxiety (LSAS), depression (HAMD), and age in years (i.e., residuals) at baseline. Suicidal ideation = Inventory of Depression and Anxiety Symptoms – Second Version suicidality subscale; LSAS = Liebowitz Social Anxiety Scale; HAMD = Hamilton Depression Rating Scale; gray circles and gray fit line = social anxiety disorder; black triangles and black fit line = major depressive disorder

Figure 3.

Scatterplot illustrating relationship between suicidal ideation and residualized RewP at FCz for gain (i.e., win) controlling for anxiety (LSAS), depression (HAMD), and age in years (i.e., residuals) at baseline (left panel). Scatterplot illustrating relationship between suicidal ideation and residualized FN at FCz for loss controlling for anxiety (LSAS), depression (HAMD), and age in years (i.e., residuals) at baseline (right panel). Suicidal ideation = Inventory of Depression and Anxiety Symptoms – Second Version suicidality subscale; LSAS = Liebowitz Social Anxiety Scale; HAMD = Hamilton Depression Rating Scale; gray circles and gray fit line = social anxiety disorder; black triangles and black fit line = major depressive disorder

Figure 4.

Bars depicting average change in symptom severity collected every two weeks across treatment for patients assigned to CBT (dark gray bars) or ST (light gray bars); error bars = standard error of the mean. Composite Symptom Score = Hamilton Depression Rating Scale and Liebowitz Social Anxiety Scale CBT = cognitive behavioral therapy; ST = supportive therapy