Cognitive impairment is a core but often overlooked feature of depression, and is rarely captured outside occasional clinic-based assessments. Cognition, however, is dynamic and contextual, linked to daily life behaviours. Smartphones enable repeated measurements of cognitive functioning in daily life (i.e., performance tasks and self-reported measures) and wearables can be used to track behaviours that may impact it. Using data from over 500 participants in the RADAR-MDD cohort, Marcos Ross-Adelman and colleagues examined whether sleep duration, step count, and smartphone screen time are associated with cognitive functioning in Major Depressive Disorder (MDD). They analysed these correlations between persons and within persons over time.
Key findings
- Higher step count was consistently associated with better cognitive functioning, both between individuals and within individuals over time,
- Screen time showed more complex relationships, with increases linked to poorer self-reported cognitive functioning but better scores on the performance tasks,
- Sleep duration also showed associations, with higher and lower sleep times linked to worse performance on the cognitive tasks.
Conclusion
Wearables and smartphones have the potential to capture real world indicators of cognitive health in individuals with depression. Data collected with these devices could inform interventions aimed at supporting cognitive health in MDD. These findings suggest that simple, modifiable behaviours, such as increasing step count, may be promising targets for intervention.
Overall, researchers can get more insight into people’s daily lives and clinicians could use these digital markers to monitor their patients more closely.
