Course of cognitive impairment following attempted suicide in older adults

Abstract

Objective: Cognitive impairment has been associated with late-life suicidal behavior. Without longitudinal data it is unclear whether these are transient features of a depressive state or stable impairments. We examined longitudinally the course of cognitive impairment in older adults with depression and a history of suicide attempt.

Methods: We investigated the persistence of cognitive impairment over time in 198 depressed older adults (age >60); 91 suicide attempters, 39 depressed individuals with suicidal ideation (ideators), and 68 non-suicidal depressed adults assessed over a 2-year period at four time points. We used linear mixed effects modeling to examine group differences in trajectories of cognitive decline over 2 years, using the Mini-Mental State Examination (MMSE), Mattis Dementia Rating Scale (DRS), and Executive Interview (EXIT).

Results: Over the 2-year period, suicide attempters performed significantly worse than both suicide ideators and non-suicidal depressed older adults on the MMSE (mean difference: from ideators: -0.88, p = 0.02; from non-suicidal depressed: -1.52, p < 0.01), while on the EXIT and DRS, suicide attempters performed significantly worse than non-suicidal depressed older adults (mean difference: in EXIT: -1.75, p = 0.01; in DRS: 3.04, p < 0.01; in MMSE: 1.15, p < 0.01). Cognitive impairment in suicide attempters partly resolved, as indicated by a group × time interaction on the DRS (p = 0.039), but not the EXIT (p = 0.58) or the MMSE (p = 0.08).

Conclusions: Cognitive impairment in late-life suicidal behavior appears to involve both a stable and a state-related component.

Keywords: cognitive; depression; executive function; older adults; suicide.

Figure 1. Predicted MMSE scores over the 2-year follow-up period for Suicide Attempters, Suicide Ideators, and Non-suicidal Depressed Older Adults

Figure 1 depicts the trajectories of MMSE scores over a 24-month follow-up period for suicide attempters, ideators, and nonsuicidal depressed older adults, and shows that suicide attempters performed significantly worse than both suicide ideators and the nonsuicidal depressed group across the four time points. There was a trend such that suicide attempters showed improvement and the nonsuicidal depressed group showed decline over time, but this failed to reach significance. *All analyses included age, sex, and education as covariates. Age was coded in years, education was coded as years of education, and sex was coded as 1=male and 2=female. **MMSE scores of 189 participants at baseline, N=132 with at least 2 data points, N=112 with least 3 data points, and N=81 of participants with 4 data points.

Figure 2. Predicted EXIT scores over the 2-year follow-up period for Suicide Attempters, Suicide Ideators, and Non-suicidal Depressed Older Adults

Figure 2 depicts the trajectories of EXIT scores over a 24-month follow-up period for suicide attempters, ideators, and nonsuicidal depressed older adults, with higher EXIT scores reflecting worse performance. Suicide attempters performed significantly worse on that EXIT than the nonsuicidal depressed group across the four time points. There was no evidence of decline in executive performance over the four time points across the groups. *All analyses included age, sex, and education as covariates. Age was coded in years, education was coded as years of education, and sex was coded as 1=male and 2=female. **EXIT scores of 199 participants at baseline, N=147 with at least 2 data points, N=103 with least 3 data points, and N=74 of participants with 4 data points.

Figure 3. Predicted DRS scores over the 2-year follow-up period for Suicide Attempters, Suicide Ideators, and Non-suicidal Depressed Older Adults

Figure 3 depicts the trajectories of DRS scores over a 24-month follow-up period for suicide attempters, ideators, and nonsuicidal depressed older adults, and shows that suicide attempters performed significantly worse on the DRS than the nonsuicidal depressed group across the four time points. The rate of change in performance on the DRS differed across three groups, such that the nonsuicidal group showed a trend toward decline in performance, and the suicide attempters and ideators showed a trend towards improvement in performance; however, the trajectory of change in DRS performance for each group failed to reach significance. *All analyses included age, sex, and education as covariates. Age was coded in years, education was coded as years of education, and sex was coded as 1=male and 2=female. **DRS scores of 210 participants at baseline, N=157 with at least 2 data points, N=105 with least 3 data points, and N=70 of participants with 4 data points.