Study Results Indicate Purpose in Life Declines with Emergence of Cognitive Impairment

Purpose in life, the feeling that one’s life is meaningful with direction, is a key component to psychological well-being that has been linked to stronger cognitive health in adults. For those with dementia, maintaining a purpose in life has the potential to reduce apathy related to the condition. Psychological changes across cognitive impairment has previously focused on clinical markers of mental health (eg, anxiety and depression) but did not address associations with purpose in life. A recent study published in JAMA Network Open evaluated the changes in purpose in life prior to and after cognitive impairment.

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This cohort study examined 50,985 assessments of purpose in life from 22,668 participants in the Health and Retirement Study (HRS) and 53,880 assessments from 10,786 participants in the National Health and Aging Trends Study (NHATS). In both cohorts, participants were given a cognitive battery to assess cognitive status at each wave. At baseline, patients in the HRS cohort had a mean age of 64.76 years and NHATS had a mean age of 76.82 years.

In the HRS cohort, purpose in life was assessed with the Purpose in Life subscale, which required participants to rate 7 items (eg, “I have a sense of direction and purpose in my life”) on a scale of 1 (strongly disagree) to 6 (strongly agree). When needed, the items were reverse scored in the direction of greater purpose, and the mean was calculated across responses. Further, NHATS measured purpose of life with the item “My life has meaning and purpose”, rated on a scale of 1 (agree a lot) to 3 (do not agree at all), and the item was reverse scored in the direction of greater purpose.

In HRS, cognitive function was measured by the sum of participants’ performance on 3 cognitive tasks with a possible range of 0 to 27: word recall, serial 7s, and backward counting. Cognitive impairment was defined as a score less than or equal to 11, based on a validated threshold.

The NHATS used a standardized algorithm to calculate cognitive impairment from reported diagnosis, objective cognitive function (eg, episodic memory, orientation, and executive function), and the AD8 Dementia Screening Interview, with probable (scores ≤1.5 SDs below the mean in at least 2 cognitive domains, reported physician diagnosis of dementia, or scored ≥2 on the AD8 Dementia Screening Interview) and possible (1 cognitive domain score ≤1.5 SDs below the mean) dementia being combined into any impairment category.

Across the 2 cohorts, declines in purpose in life were observed across the preclinical and clinical stages of cognitive impairment. The decline was greater during cognitive impairment, and in clinical settings. In the HRS cohort, a total of 6794 participants (30%) had scored in the cognitive impairment range over the course of the study. This population was also older, had a lower education level, and scored lower in purpose of life compared to those without cognitive impairment. Similarly, the NHATS group had a total of 4446 participants (41.2%) score in the cognitive impairment range and had a lower purpose in life score.

Further, after accounting for normative change in purpose over time, evidence showed a change in purpose both before and during cognitive impairment in the HRS cohort. Purpose in life had declined in the years leading to the development of cognitive impairment, then declined further during cognitive impairment.

Prior to the development of cognitive impairment, the estimated decline in purpose over a decade was -0.12 (95% confidence interval [CI], -0.17 to -0.07; P < .001) in HRS and -0.10 (95% CI, -0.20 to -0.01; P = .03) in NHATS. Further, compared with the estimated decline prior to the development of impairment, the estimated decline in purpose during cognitive impairment over a decade was approximately 3 times greater in HRS (b = −0.35; 95% CI, −0.41 to −0.29; P < .001) and 4 times greater in NHAT (b = −0.44; 95% CI, −0.53 to −0.34; P < .001). Despite the differences between the 2 cohorts (eg, purpose assessed with different measures, cognitive impairment based on different classification algorithms, and difference in age), the pattern of change in purpose both before and during cognitive impairment was similar across the 2 groups.

Prior research had primarily focused on the associations between purpose and healthier cognitive outcomes across older adulthood, and less work had examined how associations of purpose may change with declines in cognition. Further, the current research is significant in providing context of cognitive impairment and purpose in life, which may become important as effective treatments for dementia are developed.

Limitations of the study include the use of performance-based measures to define cognitive impairment in participants, the focus on early stages of cognitive impairment, and the lack of generalizability due to both samples being from the United States. Further, the limited number of assessments, notably in HRS, therefore quadratic terms should be interpreted with this limitation in consideration. The study authors emphasize that prior to and during cognitive impairment, interventions to maintain purpose of life may be helpful in supporting both psychological and cognitive health.

Reference

Sutin AR, Luchetti M, Stephan Y, Terracciano A. Change in Purpose in Life Before and After Onset of Cognitive Impairment. JAMA Netw Open. 2023;6(9):e2333489. doi:10.1001/jamanetworkopen.2023.33489