Apathy and depression: Which clinical specificities?

Abstract

BackgroundEver since it was first defined, apathy has been described as a transnosographic entity, involved in many neuropsychiatric disorders not least depression. Owing to its impact on therapeutic outcomes and morbidity, this clinical dimension is of considerable interest in the pathophysiology of depression. However, the literature does not adequately emphasize the links between depression and apathy. MethodsIn a prospective open-cohort study of 70 depressed patients (from November 2014 to June 2015), we sought to compare the clinical and neuropsychological profiles of apathetic versus nonapathetic depressed patients. ResultsAfter controlling for confounding factors (age, duration of disease, Selective Serotonin Reuptake Inhibitor, Post Traumatic Stress Disorder comorbidity, Forward Span), we found negative link between apathy and anhedonia (t-value = −2.56; p = .014). Thus, we found a close to significance link between anxiety and apathy (t-value = −1.89; p = .065). Furthermore, apathetic depressed patients had cognitive deficits, notably in verbal working memory (F = 5.875, p = .04). ConclusionsThe link between anhedonia and apathy highlights the difference between the consumption and programming of pleasure. The cognitive impairments of apathetic depressed patients may have an impact on their ability to allocate resources appropriately. The relationship between anxiety and apathy has been discussed in light of lack of insight. Taken together, results indicate that the apathy dimension subtends two clinical profiles of depression, which can be viewed as different pathophysiological clusters, as they probably affect two distinct networks. Further studies are needed to test this clinical hypothesis in the light of neurobiology.