Assessing anhedonia in depression: Potentials and pitfalls

Abstract

The resurgence of interest in anhedonia within major depression has been fuelled by clinical trials demonstrating its utility in predicting antidepressant response as well as recent conceptualizations focused on the role and manifestation of anhedonia in depression. Historically, anhedonia has been conceptualized as a “loss of pleasure”, yet neuropsychological and neurobiological studies reveal a multifaceted reconceptualization that emphasizes different facets of hedonic function, including desire, effort/motivation, anticipation and consummatory pleasure. To ensure generalizability across studies, evaluation of the available subjective and objective methods to assess anhedonia is necessary. The majority of research regarding anhedonia and its neurobiological underpinnings comes from preclinical research, which uses primary reward (e.g. food) to probe hedonic responding. In contrast, behavioural studies in humans primarily use secondary reward (e.g. money) to measure many aspects of reward responding, including delay discounting, response bias, prediction error, probabilistic reversal learning, effort, anticipation and consummatory pleasure. The development of subjective scales to measure anhedonia has also increased in the last decade. This review will assess the current methodology to measure anhedonia, with a focus on scales and behavioural tasks in humans. Limitations of current work and recommendations for future studies are discussed.

Anhedonia but not passive floating is an indicator of depressive‑like behavior in two chronic stress paradigms

“…The appearance of anhedonia in depression patients as well as in animals with depressive-like conditions may be a consequence of impairment of the reward mechanisms (Rizvia et al 2016). In the brain, activity of dopaminergic (DA) neurons of the ventral tegmental area (VTA) innervating nucleus accumbens plays an important role in these mechanisms.…”

Valuation in major depression is intact and stable in a non-learning environment

“…These studies have typically used reward learning and other tasks that provide feedback about rewards and focused on individuals’ responses at this feedback or ‘reward outcome’ phase (see Rizvi et al 7. for review).…”

The clinical relevance of qualitatively distinct subtypes of depression

“…Anhedonia has also been seldom studied, partly due to its inconsistent conceptualization in depression 8 . Aspects of anhedonia (e.g., low interest-activity), have been found to predict poor antidepressant outcome and prolonged time to remission 8 .…”

“…The l-opioid receptor system is involved not only in physical pain but also in the modulation of social pain, and represents a relevant target for suicide prevention. A four-week study in patients with elevated suicidal ideation showed that an ultra-low dose of sublingual buprenorphine was more effective than placebo in the reduction of that ideation 8 . A call for caution is finally needed regarding the current risk of psychiatric patients to undergo physician-assisted suicide.…”

“…The episodic pattern of the clinical course, which is among the strongest correlates of lithium response, is also familial 8 . There are also accumulating data on biological markers specific to these patients and differentiating them from lithium non-responders, including most recently data from studies of neurons derived from induced pluripotent stem cells 9 .…”