Reduced Reward Learning Predicts Outcome in Major Depressive Disorder

Abstract

Background Reduced reward learning might contribute to the onset and maintenance of major depressive disorder (MDD). In particular, the inability to utilize rewards to guide behavior is hypothesized to be associated with anhedonia, a core feature and potential trait marker of MDD. Few studies have investigated whether reduced reward learning normalizes with treatment and/or reward learning predicts clinical outcome. Our goal was to test that MDD is characterized by reduced reward learning, especially in the presence of anhedonic symptoms, and to investigate the relationship between reward learning and MDD diagnosis after 8 weeks of treatment. Methods Seventy-nine inpatients and 63 healthy controls performed a probabilistic reward task yielding an objective measure of participants’ ability to modulate behaviour as a function of reward. We compared reward responsiveness between depressed patients and controls, as well as high vs. low anhedonic MDD patients. Further, we evaluated whether reward learning deficits predicted persistence of MDD after 8 weeks of treatment. Results Relative to controls, MDD patients showed reduced reward learning. Moreover, patients with high anhedonia showed diminished reward learning compared to patients with low anhedonia. Reduced reward learning at study entry increased the odds of a persisting diagnosis of MDD after 8 weeks of treatment (OR: 7.84). Conclusions Our findings indicate that depressed patients, especially those with anhedonic features, are characterized by an impaired ability to modulate behaviour as a function of reward. Moreover, reduced reward learning increased the odds for the diagnosis of MDD to persist after 8 weeks of treatment.

Dissociable temporal effects of bupropion on behavioural measures of emotional and reward processing in depression

“…In such tasks, HCs typically develop a reward response bias, learning to choose the stimulus associated with high-probability win and avoid the stimulus associated with high-probability loss in order to maximize payoffs. MDD patients fail to develop a reward response bias, resulting in reduced likelihood of choosing the stimulus associated with high-probability win [19][20][21]. The MDD group was found to be significantly less likely to choose the correct symbol in the win condition associated with highprobability win compared with the HC group at baseline in the present study, again consistent with previous research.…”

“…Depressed patients display blunted responsiveness to reward [18] and fail to develop a response bias towards high-probability win during probabilistic instrumental learning tasks [19][20][21]. These impairments correlate specifically with the severity of self-reported anhedonia, independently of overall depression severity [21][22][23][24]. Building on pre-clinical evidence for a role of dopamine in reward [25,26], it has been hypothesized that the anhedonia and underlying impaired reward processing in depression involve changes in the function of the dopamine system.…”

Blunted cardiovascular reactivity during social reward anticipation in subclinical depression

“…The wealth of empirical studies strongly suggest that individuals with clinical and subclinical depression are impaired in their response to rewards both during the anticipatory (i.e., motivational) phase and during the consummatory (i.e., emotional) phase (for a detailed discussion about the distinction between these two phases, see Berridge and Robinson, 2003;Gard et al, 2006). Specifically, depressed individuals report less anticipated pleasure (e.g., Chentsova-Dutton and Hanley, 2010), show impaired reward-learning behavior (e.g., Huys et al, 2013;Liu et al, 2011;Vrieze et al, 2013), demonstrate impaired reward-related decision making (e.g., Kunisato et al, 2012;Treadway et al, 2012), have reduced activity in approach-related cortical regions (e.g., Shankman et al, 2013; for a review see Thibodeau et al, 2006), and show altered activity in reward-related brain regions (for a review see Zhang et al, 2013). Recently, we have shown reduced effort-related cardiovascular reactivity during goal pursuit in subclinical depression (Brinkmann and Franzen, 2013;Brinkmann et al, 2009;Brinkmann, 2015, 2016a).…”

Reward Processing in Motivational and Affective Disorders

“…In a series of studies, Pizzagalli and colleagues have investigated impairments in the ability, or propensity, to develop a response bias toward stimuli that are more frequently rewarded than others using a probabilistic reward task (Pizzagalli et al, 2005(Pizzagalli et al, , 2008Pechtel et al, 2013;Vrieze et al, 2013). The task has been applied to patients with varying degree of depressive and anhedonia symptoms and findings from these studies consistently show evidence of impaired reward learning.…”

“…In the first study, Pizzagalli et al (2005) showed that in participants with low levels of depressive symptoms there was an increase in the response bias over time, which was not present in participants with high levels of depressive symptoms. Subsequent studies of clinical populations show evidence of diminished reward responsiveness in depressed patients compared with controls (Pizzagalli et al, 2008;Vrieze et al, 2013), in patients with remitted depression compared with controls (Pechtel et al, 2013), and in depressed patients with high vs. low levels of anhedonia symptoms (Vrieze et al, 2013).…”