Lateralised attentional disruption and resource conservation in persistent depression and anhedonia

Anhedonia – a pervasive loss of interest or enjoyment in relation to previously valued stimuli - is a central feature of clinical depression. A series of studies investigated alterations in perceptual sensitivity and attention, and their relation to anhedonia, in participants with persistent depressive illness in comparison to healthy controls. Study 1 measured perceptual sensitivity in the somatic and auditory modalities while minimising attentional influences. Study 2 maximised attentional influences to assess their impact on perceptual sensitivity in the same modalities. Perceptual sensitivity did not differ between groups in either study. Both studies found evidence of lateralised attentional deficits suggestive of subtle left-sided neglect in the depressed samples. In both studies, lateralised attentional deficits were associated with anhedonia above and beyond depression severity. Study 3 demonstrated through simulation that a single lateralised attentional lapse model could predict the key outcomes in both empirical studies, and additionally demonstrated the plausibility of a resource conservation strategy as a data-generating process among depressed participants. In conclusion, the studies support the novel insight that anhedonia may be related to disruptions in brain networks subserving stimulus-driven attention, with a potential contribution of resource conservation strategies that reduce access to precise sensory information.