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More details on the new meta-analysis on behavioural reward processing impairment in #depression by @karelkieslich, @CiaranPsi, @_a_nair, @jonroiser, @GlynLewis9 and I in @JAMAPsych https://twitter.com/JAMAPsych/status/1345053854954639360
We carried out a meta-analysis on behavioural case-control reward processing studies in order to find out whether clinically depressed people have reward-processing impairments https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2768364?guestAccessKey=f3d12355-4361-4711-a345-cb88d70362d1
The meta-analysis contained 48 studies, with an overall sample size of 1387 healthy controls and 1767 individuals with depression
Overall, depression was associated with small to medium impairments in reward-processing (SMD = 0.345; 95% CI, 0.209-0.480). None of the variance was explained by the medication status of the depressed individuals.
As reward processing encompasses a number of processes, we also looked at 4 subcomponents:
Option valuation reflects how individuals evaluate reward-related options when they are given explicit information about those options. Depressed individuals have a small to medium impairment in option valuation (SMD, 0.309; 95% CI, 0.147-0.471)
Reward response vigour reflects the speed with which an individual performs an action to obtain a reward. Depressed individuals have a small to negligible (non-significant) impairment in reward response vigour (SMD, 0.083; 95% CI, −0.144 to 0.309)
Reward bias reflects the tendency to choose more frequently rewarded stimuli in perceptual tasks. Depressed individuals have a medium to large impairment in reward bias (SMD, 0.644; 95% CI, 0.270-1.017)
Reinforcement learning is the process by which an individual uses reward feedback to change their behaviour in the future. Depressed individuals have a small to medium impairment in reinforcement learning (SMD, 0.352; 95% CI, 0.115-0.588)
We looked at whether impaired cognition or anhedonia moderated reward processing impairment. We didn’t find any evidence for this but these analyses were likely underpowered.
Take-home message: depressed individuals experience significant behavioural reward-processing impairments, most prominently on reward bias.
