Role of Reward Sensitivity and Processing in Major Depressive and Bipolar Spectrum Disorders

Abstract

Since Costello’s (1972) seminal Behavior Therapy article on loss of reinforcers or reinforcer effectiveness in depression, the role of reward sensitivity and processing in both depression and bipolar disorder has become a central area of investigation. In this article, we review the evidence for a model of reward sensitivity in mood disorders, with unipolar depression characterized by reward hyposensitivity and bipolar disorders by reward hypersensitivity. We address whether aberrant reward sensitivity and processing are correlates of, mood-independent traits of, vulnerabilities for, and/or predictors of the course of depression and bipolar spectrum disorders, covering evidence from self-report, behavioral, neurophysiological, and neural levels of analysis. We conclude that substantial evidence documents that blunted reward sensitivity and processing are involved in unipolar depression and heightened reward sensitivity and processing are characteristic of hypomania/mania. We further conclude that aberrant reward sensitivity has a trait component, but more research is needed to clearly demonstrate that reward hyposensitivity and hypersensitivity are vulnerabilities for depression and bipolar disorder, respectively. Moreover, additional research is needed to determine whether bipolar depression is similar to unipolar depression and characterized by reward hyposensitivity, or whether like bipolar hypomania/mania, it involves reward hypersensitivity.

Hypomania and depression associated with distinct neural activity for immediate and future rewards

“…Our results also support models of reward sensitivity that posit that differential profiles of reward‐related neural activity may predict clinical risk for bipolar spectrum versus unipolar depressive disorders (see Nusslock & Alloy, , for review). Despite numerous studies that separately investigated relationships between neural activity and vulnerability for hypomania and depression (see Alloy et al, , for review), the present results are the first to report that hypomanic and depressive symptoms are associated with differential profiles of feedback‐related ERPs within the same sample (see Figures , ) and to show that these associations are independent of, and significantly different from, one another (see Figure ). Although these measures are associated with opposite profiles of reward‐related neural activity, previous research indicates that hypomanic and depressive symptoms are independent constructs and represent separable, rather than opposing, psychometric dimensions (Johnson et al, ; Solomon et al, ; Youngstrom et al, ).…”

“…Prevailing theories suggest that distinct and opposite profiles of reward sensitivity constitute a preexisting risk factor for, rather than a consequence of, bipolar spectrum and unipolar depressive disorders (see Alloy, Olino, Freed, & Nusslock, , for review). Reward sensitivity relates to the value an individual places on rewards, the perceived expectation of reward receipt, and the mechanisms by which rewards are processed.…”

Reward Sensitivity Enhances Ventrolateral Prefrontal Cortex Activation during Free Choice

“…For instance, substance abuse and psychopathy are related to high levels of responsiveness to rewards (Buckholtz et al, 2010; Schneider et al, 2012; Yau et al, 2012; Tanabe et al, 2013). Reward sensitivity is also associated with negative mental-health outcomes such as greater risks for addictions (Kreek et al, 2005), alcohol abuse (Franken, 2002), eating disorders (Davis et al, 2004; Franken and Muris, 2005), and depressive disorders (Alloy et al, 2016). Consistent with our findings from reward sensitivity, bipolar patients show hypersensitivity to rewards and recruit VLPFC when anticipating rewards (Whitton et al, 2015; Chase et al, 2016), and pathological gamblers tend to reveal hyposensitivity to rewards and fail to activate the VLPFC in response to monetary rewards (de Ruiter et al, 2009).…”

Cluster analysis with MOODS‐SR illustrates a potential bipolar disorder risk phenotype in young adults with remitted major depressive disorder

“…Indeed, both MDD and BD share major depressive episodes, one reason why it is not surprising that there are overlapping traits in the literature. [1][2][3][4] Furthermore, any measurement that yields a single score for MDD likely misrepresents the heterogeneity of the disorder, 5 and does not necessarily rule out bipolar spectrum symptoms. Furthermore, early in the course of the illness, a substantial minority of those presenting with MDD will later be diagnosed with BD.…”