The bidirectional relationship between depression and cognitive function in older adults: evidence from a...

Depression is a modifiable predictor of dementia, but the effects of addressing depression to improve cognition, especially psychosocial interventions, are understudied. The underlying relationships between depressive symptoms (DS) and cognitive function (CF) are also unclear. Most prior research has been observational, lacking insight into their interactions during interventions. This study examined the longitudinal relationships between DS and CF across psychosocial interventions in older adults, modeling changes as latent variables for more accurate estimations.

The study drew on participant data from JC JoyAge, a community stepped-care program for late-life mental health. Participants (≥60 years) with mild to moderate DS (N = 4,412) completed DS and CF assessments (e.g., attention, language, orientation, memory domains) before and after the program. Latent change score models were computed to examine changes in DS and CF as well as their interaction.

On average, participants' DS and CF improved following intervention. A greater reduction in DS was associated with greater improvement in CF. Higher baseline CF predicted a greater reduction in DS, while a lower baseline DS predicted a greater improvement in global CF, attention, and memory.

The findings demonstrated the bidirectional relationships between DS and CF and showed their shared improvements during psychosocial intervention. Treating depression is expected to benefit cognition, potentially preventing cognitive decline and dementia. Combining depression and cognition components in integrated intervention approaches may enhance their reciprocal response. Early intervention at a lower depression level may achieve greater cognitive benefits.