Elevated Effort Cost Identified by Computational Modeling as a Distinctive Feature Explaining Multiple Behaviors in Patients With Depression.

BACKGROUND: Motivational deficit is a core clinical manifestation of depression and a strong predictor of treatment failure. However, the underlying mechanisms, which cannot be accessed through conventional questionnaire-based scoring, remain largely unknown. According to decision theory, apathy could result either from biased subjective estimates (of action costs or outcomes) or from dysfunctional processes (in making decisions or allocating resources). METHODS: Here, we combined a series of behavioral tasks with computational modeling to elucidate the motivational deficits of 35 patients with unipolar or bipolar depression under various treatments compared with 35 matched healthy control subjects. RESULTS: The most striking feature, which was observed independent of medication across preference tasks (likeability ratings and binary decisions), performance tasks (physical and mental effort exertion), and instrumental learning tasks (updating choices to maximize outcomes), was an elevated sensitivity to effort cost. By contrast, sensitivity to action outcomes (reward and punishment) and task-specific processes were relatively spared. CONCLUSIONS: These results highlight effort cost as a critical dimension that might explain multiple behavioral changes in patients with depression. More generally, they validate a test battery for computational phenotyping of motivational states, which could orientate toward specific medication or rehabilitation therapy, and thereby help pave the way for more personalized medicine in psychiatry.

Subsyndromal and syndromal depressive symptoms among older adults with schizophrenia spectrum disorder: Prevalence and associated factors in a multicenter study.

BACKGROUND: Few studies have examined the prevalence and correlates of subsyndromal and syndromal depressive symptoms (SSSD) among older adults with schizophrenia spectrum disorder. In this report, we examined the prevalence of SSSD and their associations with sociodemographic characteristics, clinical characteristics of schizophrenia, comorbidity, psychotropic medications, quality of life, functioning and mental health care utilization in a large, multicenter sample of older adults with schizophrenia spectrum disorder. METHODS: Data from the Cohort of individuals with Schizophrenia Aged 55 years or more (CSA) were used to examine the prevalence of SSSD, defined using the Center of Epidemiologic Studies Depression (CESD) scale. Clinical characteristics associated with SSSD were explored. RESULTS: Among 343 older adults with schizophrenia spectrum disorder, 78.1% had either subsyndromal (30.6%) or syndromal (47.5%) depressive symptoms. SSSD were independently associated with positive and negative symptoms, lower quality of life, non-late-onset psychosis, benzodiazepine use and urbanicity. There were no significant associations of SSSD with other sociodemographic characteristics and psychotropic medications, or with general medical conditions. We found no significant differences in the proportion of participants who were treated with antidepressants between those with syndromal depressive symptoms and those without depression (22.1% vs. 20.0%, p = 0.89). SSSD were not associated with higher mental health care utilization. LIMITATIONS: Data were cross-sectional and depression was not evaluated with a semi-structured interview. CONCLUSION: SSSD may be highly prevalent and under-assessed and/or undertreated among older adults with schizophrenia spectrum disorder. Our findings should alert clinicians about the need to assess systematically and regularly depression in this vulnerable population.