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Overview

There is extensive evidence in the research literature documenting high levels of comorbidity between physical illness and depression in later life. Among disabled elders, depression is associated with greater levels of functional disability and poorer medical outcomes.

This study builds upon the growing body of research regarding the interrelationships among chronic impairment, disability, and depression by focusing on the visually impaired elderly, for whom rates of both functional disability and depression are particularly high compared to elders with other age-related disabilities. Using a longitudinal design, the study examines the course of depression over time as it affects, and is affected by, impairment severity, functional ability and rehabilitation service utilization. Furthermore, utilizing a stress and coping conceptual model, the extent to which these relationships are mediated by personal and social resources is also examined. Most importantly, the focus on a sample seeking rehabilitation permits an empirical challenge to the assumption of inevitable, reciprocal decline in functional and depressive status among the disabled elderly. By following both the natural course of depression and the natural course of rehabilitative service utilization, the study examines the extent to which, and mechanisms by which, this nonpsychiatric intervention (i.e., vision rehabilitation) may influence short- and long-term depression status among the visually disabled elderly.

Method

A sample of visually impaired elders has been drawn from applicants to the Lighthouse, age 65 years and older. Subjects were assessed 4 times (at baseline, 6, 12 and 18 months) in order to examine both short- and long-term causal relationships among the key variables of impairment, disability, rehabilitation and depression. Depression was assessed using both a continuous symptomatology measure (CES-D) and a clinical diagnostic interview (SCID for DSM-IV). Analyses are addressing concurrent associations (cross-sectional) and prospective relationships (longitudinal) using regression and structural equation modeling (SEM) techniques.

Findings

Recruitment of the baseline sample and all follow-up data collection has been completed. A total of 584 baseline, 455 Time-2, 418 Time-3, and 386 Time-4 interviews have been conducted; with 354 participants completing all four interviews. Selected findings from ongoing analyses include:

Prevalence and Correlates of Major and Subthreshold Depression - Rates of both major and subthreshold depression among participants were higher than those found among general samples of community-based elders. Among the baseline sample (n=584), 7.2% met DSM-IV diagnostic criteria for a current major depression disorder (MDD), 26.9% had a subthreshold depression (defined as including: minor depression, dysthymia, major depression in partial remission, or significant depressive symptomatology ), while 65.9% were not depressed. Logistic analyses were conducted to identify the most salient independent factors differentiating each depressed group from the nondepressed. The three groups did not significantly differ in age, gender, race, education, marital status or living arrangements; all common risk factors for depression identified in prior research. This suggests that general sociodemographic factors may be less important as risk factors for depression when the focus is on a disabled elderly population. The profiles of independent risk factors for both depressed groups were remarkably similar. That is, compared to the nondepressed, both those with subthreshold and major depression were significantly more likely to have poorer perceived adequacy of social support, lower self efficacy, and a past history of depression. Greater functional disability and experiencing at least one negative life event in the past year were significant only in differentiating those with subthreshold depression from the nondepressed, although the odds ratios for those with major depression approached significance. The only variable to emerge as significant in differentiating elders with subthreshold versus major depression was having a past major depression which resulted in a 4.5 times greater risk of having a major, over a subthreshold depression. Thus, elders with major and subthreshold depression have very similar profiles, which highlights the importance of identifying and treating elders with both disorders.

Personal and Social Resources as Mediators of the Disability-Depression Link - Through structural equation modeling, the mediating effects of social resources (negative support and perceived adequacy and availability of social support) and personal resources (active, acceptance, and self-distraction coping, and self-efficacy) were tested. Functional disability was influenced by both subjective vision loss severity and health status, but not by clinical vision impairment (acuity and contrast sensitivity). The effect of functional disability on depression, however, was fully mediated by social resources and personal resources; with each of the latter also having direct positive effects on depression. Findings provide further support that it is not necessarily the objective severity of an impairment that is associated with disability (or depression) but the subjective experience. Findings further highlight that personal and social resources largely mediate the negative mental health effects of disability. Thus, a focus on maximizing a person's personal and social resources needs to be a critical part of any intervention for depression among disabled elders.

Depression and Rehabilitation Service Use - Findings indicated that 12% of the 6-month follow-up sample did not follow through on their application and received no services in the 6 months following the research interview. Logistic regression analyses to predict service use (yes/no), with predisposing, enabling and need factors accounted for in the equation, found that CES-D scores did not predict service use, but those with a diagnosis of major depression were 64% less likely to use any rehabilitation services. There was no significant effect of subthreshold depression on service use. Looking only at service ulitizers and using hierarchical regression models, CES-D scores again did not predict the number of service hours, but a major depression diagnosis was a significant predictor of fewer hours of service. Findings suggest that the relationship between depression and rehabilitation service use is not strictly linear and that a threshold of depression severity needs to be crossed to have a negative impact on rehabilitation service utilization.

Six-Month Change In Depression - Examination of change in depression at the 6-month follow-up (n=455) indicated that 60.4% of the Time-2 sample (n=455) were consistently not depressed, 14.5% were consistently depressed (either consistent major or subthreshold depression), 15.8% had either a remission or improvement in depression status, and 9.2% had an incident depression.

The September 11th attacks and depressive symptomatology - Given our ongoing assessments of depressive symptomatology among elders in the New York area, we were in a unique position to examine the impact the 9/11/01 attacks may have had on mental health in terms of introducing bias into our results. For this examination, we selected participants who were interviewed two months prior and two months following the September 11th attacks (n=168; 111 in the Pre-Attack Group and 57 in the Post-Attack Group). Mean CES-D scores were plotted by week. Although there was a spike in mean CES-D scores in the four days immediately following September 11th (i.e., mean score = 13.6), subsequent average scores demonstrated the normal variability. In addition, ANOVA tests were conducted comparing Pre- and Post-Attack group, age, gender, and education factors for significant differences in CES-D scores. There were no significant main effects for any of these factors, or any significant interactions between these factors and Pre/Post-Attack group status. Thus, the terrorist attacks of 9/11/01 were not found to introduce any statistically significant bias in these outcome variables of depressive symptoms.

Hearing Problems as an Added Risk Factor for Depression in Older Adults with Vision Loss - Because prior studies have shown a positive relationship between single impairments of vision and hearing and depression in older adults, it was hypothesized that vision impaired older adults who also reported difficulty with hearing would have higher levels of depression compared to their peers (controlling for comorbid health conditions and ADL ability). Results showed that the severe dual impaired group (self reported poor/very poor hearing) reported the highest average CES-D scores (M = 16.9) and were the most likely to have received a diagnosis of current major depression or any mood disorder (e.g., major or minor depression, partial remission, dysthymia).

Prescription medication, over-the-counter products, and vitamin use by visually impaired older adults - Analyses were conducted to examine the use of prescription medications, vitamins, and over-the-counter products by older adults with vision problems. The number of prescription medications taken daily ranged from 0 to 15, with a mean of 4.2, the use of daily vitamins ranged from 0 to 13 with a mean of 2.2, and over-the-counter product use ranged from 0 to 6 with a mean of .79. Aspects of health largely explained use of prescription medications and over-the-counter products, while the use of vitamins was explained by demographic variables (e.g., age, gender, and education). Further analyses examined factors associated with the use of an eye-multivitamin at both baseline and at the 18-month follow-up. Twenty percent of participants were using an eye-multivitamin at baseline, and 22% were doing so at follow-up. At baseline, those individuals with a diagnosis of macular degeneration were more likely, while African-Americans were less likely, to use an eye-multivitamin. At the 18-month follow-up, individuals who used an eye-multivitamin at baseline and those who had macular degeneration were more likely to be still using an eye-multivitamin, while those receiving Medicaid, indicating lower SES status, and those with increased disability were less likely to use one.

The Effect of Rehabilitation Service Use on Functional Disability and Depression - Over Time in Older Adults with Vision Loss - Analyses used baseline, 6- and 12-month follow-up data, and full information maximum likelihood was used to fit a mean and covariance structure model to all available data, which allowed the examination of change over time in functional disability and depression in relation to rehabilitation service hours. Results showed decreased depression at both 6- and 12-months postbaseline, but functional disability increased over time. Use of more than an average amount of rehabilitation service was associated with a significantly lower rate of increase in functional disability at Time 2 and Time 3. Rehabilitation use was not significantly associated with change in depression over time. However, associations between the functional disability and depression change variables were significant and positive. Significant positive change in depression (greater decline in symptoms) was associated with better than average status (less decline) in functional ability. This provides some evidence for an indirect effect of rehabilitation on change in depression through change in functional disability. Results show a promising impact of rehabilitative services with regard to enhanced functioning in everyday activities.

The Impact of Assistive Device Use on Disability and Depression Among Older Adults with Age-Related Vision Impairments - Adaptive technology can be conceptualized as a resource used by older adults to minimize the disabling effects of health conditions and maintain competence in everyday life. Analyses examined the contribution of optical device and adaptive aid utilization to change in functional disability and depression among older adults with age-related vision impairments. The sample for these analyses was comprised of participants (n=455) who were interviewed preservice and at the six-month follow-up. Hierarchical regression analyses were conducted with functional disability and depressive symptoms as criteria. Optical and assistive device use were entered in the final step, preceded by Time-1 criterion scores, demographics, change in disability/depression, and total rehabilitation service hours. Findings indicated that optical, but not adaptive device use, was a significant predictor of declines in functional disability and depressive symptoms over time. It is proposed that these differential effects result from the fact that optical devices allow for greater continuity in the way tasks are accomplished (i.e., reading still performed visually); while adaptive aids are more likely associated with greater disability and involve learning new methods to compensate for lost functions (e.g., talking books), and thus are not as desirable either functionally or psychologically.

Changes in Vision and Health and Change in Depression - To better understand the interrelationships of vision impairment, physical comorbidity and depression, this study examined changes in vision and health and change in depressive symptoms among participants over the first three data points using structural latent-change analysis. Variables for the measurement model included vision acuity, contrast sensitivity, self-rated health, number of health conditions, and the Center for Epidemiological Studies Depression Scale (Radloff, 1977) to estimate initial status (i.e., intercept) and change (i.e., slope) latent factors. The resultant model fit the data well. Vision status was found to worsen over time as expected. There were no overall significant changes in health and depression latent scores. There were significant effects of individual change among these latent factors over time, despite the lack of significant average change. While there were no significant effects of change in vision or initial status on health in change in depression over time, there was a significant effect of change in health on change in depression; those whose health worsened experienced an increase in depressive symptoms. Also, change in vision status was not significantly related to change in health status, which may indicate a disassociation of vision status as a health condition among participants. Findings suggest that vision rehabilitation applicants with deteriorating health are at a higher risk for an increase in depressive symptoms over time.

Publications

Horowitz, A., Brennan, M., Reinhardt, J., & MacMillan, T. (2006). The impace of assistive device use on disability and depression among older adults with age-related vision impairments. The Journals of Geretology. Series B, Psychosocial Sciences and Social Sciences, 61(5), S274-80.

Horowitz, A., & Reinhardt, J. (2006). Adequacy of the Mental Health System in Meeting the Needs of Adults Who Are Visually Impaired. Journal of Visual Impairment & Blindness, 100, 871-874.

Raykov, T., Brennan, M., Reinhardt, J.P., & Horowitz, A. (in press). Comparison of mediated effects: A correlation structure modeling approach. Structural Equation Modeling.

Brennan, M., Horowitz, A., & Reinhardt, J. P. (2003). The September 11th attacks and depressive symptomatology among older adults with vision loss in New York City. Journal of Gerontological Social Work, 40 (4), 54-72.

Horowitz, A. (2005). Depression in later life. In C. B. Fisher & R. M. Lerner (Eds.), Encyclopedia of applied developmental science, Vol. I (pp. 334-336). Thousand Oaks: Sage.

Horowitz, A. (2004). Prevalence and consequences of age-related vision impairment. Topics in Geriatric Rehabilitation, 20, (3), 185-195.

Horowitz, A. (2003). Depression and vision and hearing impairments in later life. Generations, 27, 32- 38.

Horowitz, A., Boerner, K., & Reinhardt, J. P. (2002). Psychosocial aspects of driving transitions in elders with low vision. Gerontechnology, 1 (4), 262-273.

Horowitz, A., & Reinhardt, J. P. (2000). Mental health issues in visual impairment: Research in depression, disability and rehabilitation. In B. Silverstone, M. A. Lang, B. Rosenthal, E. Faye (Eds.), The Lighthouse handbook on vision impairment and vision rehabilitation: Vol. II. Vision rehabilitation (pp. 1089-1109). New York: Oxford University Press.

Horowitz, A., Reinhardt, J. P., & Kennedy, G. (2005). Major and subthreshold depression among older adults seeking vision rehabilitation services. American Journal of Geriatric Psychiatry, 13(3), 180- 187.

Presentations

Brennan, M., Horowitz, A., & Reinhardt, J. P. (2003, August). Hearing problems increase depression in older adults with visual impairment. Poster session presented at the annual convention of the American Psychological Association, Toronto, Ontario, CA.

Brennan, M., Horowitz, A., Reinhardt, J. P., Raykov, T., & MacMillan, T. (2005, August). Changes in vision and health and change in depression. Poster presented at the annual convention of the American Psychological Association, Washington, DC.

Horowitz, A., Brennan, M., & Reinhardt, J. P. (2003, December). Disability, depression, and use of optical and adaptive aids among older adults with vision loss. Paper session presented at the International Conference on Aging, Disability and Independence, Arlington, VA.

Horowitz, A., & Reinhardt, J. P. (2001, November). Social support and depression among disabled elders. In M. Cantor (Chair), Social support networks: The influence of contextual factors. Symposium conducted at the annual scientific meeting of The Gerontological Society of America, Chicago, IL.

Horowitz, A., & Reinhardt, J. P. (2002, April). Clinical and subsyndromal depression in chronically impaired community-dwelling elders. Paper presented at the Joint Conference of The National Council on Aging and the American Society on Aging, Denver, CO.

Horowitz, A., Reinhardt, J. P., Brennan, M., MacMillan, T., & Cantor, M. (2003, November). Is depression a barrier to rehabilitation service use? Poster presented at the annual scientific meeting of The Gerontological Society of America, San Diego, CA.

Horowitz, A., Reinhardt, J. P., Brennan, M., & Raykov, T. (2004, April). Mediating the disability-depression link: The role of personal and social resources. Paper presented at the 2004 Joint Conference of the American Society on Aging and The National Council on the Aging, San Francisco, CA.

MacMillan, T., Cantor, M., Horowitz, A., Reinhardt, J., & Brennan, M. (2004, November). Activity level and satisfaction among chronically impaired older adults: The case of vision impairment. Paper presented at the annual scientific meeting of the Gerontological Society of America, Washington, D.C.

MacMillan, T., Horowitz, A., & Reinhardt, J. P. (2002, April). Prescription medication, over-the-counter products, and vitamin use by visually impaired older adults. Paper presented at the Joint Conference of The National Council on Aging and the American Society on Aging, Denver, CO.

MacMillan, T., Reinhardt, J. P., & Horowitz, A. (2003, March).Vitamin and herbal supplement use over time by community-dwelling older adults. Paper presented at the annual joint meeting of the American Society on Aging and National Council on Aging in Chicago, IL.

Reinhardt, J. P., Horowitz, A., Raykov, T., MacMillan, T., & Brennan, M. (2004, November). Rehabilitation service use, functional disability, and depression over time in older adults with vision loss. Paper presented at the annual scientific meeting of the Gerontological Society of America, Washington D.C.

Investigators: Amy Horowitz, DSW, Principal Investigator
Joann P. Reinhardt, PhD, Co-Investigator
Mark Brennan, PhD, Data Analyst
Verena Cimarolli, MA, Research Coordinator (to 7/2001)
Thalia MacMillan, MSW, Research Coordinator (from 7/2001)

Funded by: National Eye Institute

Project Period: October 1999 - September 2004

 

 

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