Depressive individuals show decreased cognitive functioning

Two studies conducted in China suggest that individuals with depressive symptoms tend to score lower on measures of cognitive functioning. However, participants who were physically active, maintained an optimal sleep duration, and reported an overall healthy lifestyle showed better cognitive performance—regardless of whether they experienced depressive symptoms. The link between depression and reduced cognitive function appeared to be weaker in this group. The findings were published in the Journal of Affective Disorders.

Depression is a mental health disorder characterized by persistent sadness, loss of interest, and diminished ability to function in daily life. Symptoms can last for weeks or months and may become chronic. People with depression often experience changes in sleep, appetite, energy, and motivation. Cognitive functions such as memory, attention, and concentration are also commonly affected.

Depressed individuals may experience slowed thinking, making it harder to make decisions or solve problems. They often display negative cognitive biases, focusing more on failures, threats, or losses than on positive information. Executive functions like planning and organizing are frequently impaired, which can interfere with work and daily responsibilities. Rumination, or repetitive negative thinking, is another common cognitive feature that can maintain and exacerbate depressive symptoms. These cognitive difficulties may persist even after mood symptoms improve.

Study author Shengli Chen and his colleagues aimed to investigate the relationship between depressive symptoms, lifestyle habits, and cognitive functioning among middle-aged and older Chinese adults. Previous research has identified several lifestyle factors that may influence the risk of cognitive decline. The researchers sought to understand how these lifestyle factors might interact with depressive symptoms.

Participants were adults over 40 years old from the provinces of Hubei and Shanghai. The study included 7,756 individuals from Hubei and 4,751 from Shanghai. In Hubei, the average age was 68 years, and 53% of participants were women. In Shanghai, the average age was 72, with 62% female participants.

Participants completed assessments of depression using the 15-item Geriatric Depression Scale and were evaluated for cognitive function using the Mini-Mental State Examination. They also provided information about their demographic characteristics (such as marital status and education), lifestyle habits (including smoking, alcohol consumption, physical activity, waist circumference, and sleep duration), and medical history (such as hypertension, diabetes, and cardiovascular disease) through structured interviews.

The results indicated that individuals with more severe depressive symptoms tended to have lower cognitive function scores. They were also more likely to meet the criteria for mild cognitive impairment. In contrast, those who were physically active, slept for an optimal duration at night, and scored higher on an index of healthy lifestyle behaviors tended to show better cognitive performance. Notably, among participants who followed these healthy behaviors, the negative association between depression and cognitive functioning was reduced.

“Depressive symptoms are associated with impaired cognitive function and this association could be attenuated by healthy lifestyles”, study authors concluded.

The study sheds light on the links between depression and cognitive functioning. However, it should be noted that the design of this study does not allow any causal inferences to be derived from the results.

The paper, “Associations of depressive symptoms and lifestyles with cognitive function: results from two cross-sectional studies among middle-age and older Chinese populations,” was authored by Shengli Chen, Wencai Ke, Xin Guan, Shiru Hong, Sheng Wu, Zirong Yu, Jie Lin, Chenming Wang, Ming Fu, Yang Xiao, Yuhan Zhou, Chenliang Liu, Guorong Zhong, Yingqian You, Yuxi Wang, Hui Zhao, Yichi Zhang, Yansen Bai, Zhengce Wan, Yong Lin, and Huan Guo.