This briefing summary provides an overview of some of the issues involved with depressive symptoms and clinical depression in people with disabilities, as well as a discussion of prevalence.
Definition of Depressive Symptoms and Clinical Depression
First, it is important to distinguish between dysthymic disorder (symptoms of chronic, mild depression persisting for at least 2 years in adults and 1 year in children) and clinical depression or major depressive disorder. Dysthymic disorder affects approximately 5.4 percent of the U.S. population age 18 and older during their lifetime. This figure translates to about 10.9 million American adults. About 40 percent of adults with dysthymic disorder also meet criteria for major depressive disorder or bipolar disorder in a given year.1
Depressed mood is only one of many other symptoms of clinical depression. Other symptoms of clinical depression, as outlined by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), include decreased interest or pleasure in nearly all activities for most of nearly every day of two weeks (noted by the patient or by others), a marked loss or gain of weight (such as five percent in one month) or markedly decreased or increased appetite, excessive or not enough sleep, agitated or retarded activity, fatigue or loss of energy, feelings of worthless or guilt, trouble thinking or concentrating, and repeated thoughts about death (other than the fear of dying), suicide (with or without a plan) or has made a suicide attempt. These symptoms cause clinically important distress or impair work, social or personal functioning and are not directly caused by the loss of a loved one or a general medical condition or the use of substances, including prescription medications.2
The DSM-IV has been the basis for measurement instruments such as the Centers for Epidemiological Studies of Depression Scale (CES-D)3, used to assess prevalence of clinical depression in a population. The CES-D, a short, self-reporting scale requiring the participant to indicate how often he or she felt or behaved during the past week, was used in one study to assess depressive symptoms in multiple sclerosis patients4. It is important to determine a definite diagnosis of clinical depression before considering treatment with medications, since antidepressants are generally not prescribed for depressed mood alone, as opposed to clinical depression.
Studies of youth with disabilities and depression generally seem to address depressive symptoms only and not the prevalence of clinical depression in children and adolescents. It is helpful to examine these studies, however, since as previously mentioned, many people with depressive symptoms or dysthymic disorder also meet criteria for major depressive disorder. One study found high rates of depressive and anxiety disorders in children and adolescents with chronic fatigue syndrome (CFS)5. A literature review on the natural history and correlates of co-morbid diabetes and depression in children and adolescents found that children with diabetes have a two-fold greater prevalence of depression, and adolescents up to three-fold greater, than youth without diabetes.6
Many studies on youth with disabilities and depression address depression in the context of other research outcomes (e.g. pain and quality of life). Since pain is associated with disability and correlates with depression, it is understandable why so many individuals with disabilities suffer from depression. In one study of pediatric pain patients suffering from chronic daily headaches, it was found that chronic pain had a substantial impact on the children’s lives. Also, a correlation was found between depression and functional disability7. In another study examining the associations among disease status, social competence, and depressive symptoms in children with juvenile rheumatic disease (JRD), pain, peer rejection, and problematic social behavior were all positively associated with depressive symptoms8.
A study of adolescents in 7th to 12th grades found that adolescents with disabilities reported a lower Quality of Life than adolescents without disabilities. Depressive symptoms were significant covariates in the relationship between disability and Quality of Life9. In addition, one publication stated that as a child with spina bifida grows from a child through adolescence, it is common for him or her to experience problems with confidence, self-esteem, body image, and depression.10
Depressive symptoms and clinical depression can follow individuals with disabilities from childhood through adolescence and adulthood. Reporting of depressive symptoms and clinical depression can be based on relatively informal self-surveys or more formal diagnoses based on tests administered by mental health professionals. The disability offices of several state health departments have conducted random digit telephone protocols which include self-reporting of adults with disabilities. These protocols examine the prevalence of physical problems, affective conditions and sensory problems of people with disabilities in the various states. Findings from several states were consistent with each other, concluding that the incidence of depressive symptoms in individuals with disabilities is higher than in individuals without disabilities.11 12 13 14 15 The Washington report suggests the incidence of depressive symptoms in individuals with disabilities could be even higher than reported, and adults with depressive symptoms are often missed in surveys. This is due to the fact that depression is often stigmatizing and some survey respondents will not report having this condition, and emotional impairments such as depression are often intermittent or controlled by medication and may not be reported as limiting at the time of the survey. In fact, these are point in time estimates. Lifetime prevalence is probably much higher.
Among other topics, the protocols focused on frequent depression, which was defined as being depressed for 15 or more days of the month. Frequent depression was reported by 30% (Massachusetts), 32.4% (New Mexico), and 34.6% (North Carolina) of those people with disabilities requiring assistance of some kind, and 14% (Massachusetts), 13.8% (New Mexico), and 15% (North Carolina) of those people with disabilities not requiring assistance, compared to around 4% among the no-disability group (Massachusetts, New Mexico, and North Carolina). The Rhode Island protocol showed that 29.8% of people with severe disabilities suffered from frequent depression, compared to 14.6% of people with moderate disabilities and 4.2% of people with no disabilities. These results show that compared with the no disabilities group, people with severe disabilities were 7 times more likely to report frequent depression.
On a related item, protocols showed that respondents with disabilities requiring assistance (21%—MA, 17.7%—NM, 7.7%—NC) and not requiring assistance (10%—MA, 8.7%—NM, 11.9%—NC) were more likely to report being dissatisfied or very dissatisfied with life than adults without disabilities (3%—MA, 3.1%—NM, 4.1%—NC). As well, the Rhode Island survey showed that 20.8% of people with severe disabilities said they were either very dissatisfied or dissatisfied with their lives, compared with only 10.3% for those with moderate disabilities and 4.2% for those with no disabilities. The Washington protocol reported 13% of the respondents were very dissatisfied or dissatisfied with life, compared to 2% of the respondents without disabilities.
Intellectual disability poses an unusual challenge, due to communication difficulties in this population. Although it has been accepted that depression can occur in adults with intellectual disability (ID), there are difficulties in its assessment and diagnosis, which impacts on treatment choice and outcome16. One study, however, described the development of a scale for individuals with learning disability called The Glasgow Depression Scale for people with a Learning Disability (GDS-LD)17, which was found useful in screening, monitoring progress and appraising outcome.
Depressive symptoms are sometimes under-recognized and under-treated, often complicated by cognitive impairment, co-morbid medical illness and adverse life events. Yet, depression should not be overlooked; in one study, depression was found to be the most common psychiatric condition among residents with multiple sclerosis (MS) in a nursing facility18. In this study, a total of 14,009 people with MS at admission to a nursing facility were analyzed using the Minimum Data Set and 36% also had depression. This study found that most MS residents with depression did not receive mental health services, indicating the need for nursing facilities to improve the mental healthcare provided to residents with MS with depression.
Concerning the prevalence of clinical depression, one study involving individuals with traumatic brain injury (TBI) adopted a longitudinal design; admissions to a level 1 trauma service were assessed just before discharge and 3 and 12 months after their injury. Structured clinical interviews were used to assess anxiety disorders, depressive disorders, and substance use disorders. Posttraumatic stress disorder (PTSD) and major depressive disorder were the most frequent diagnoses at both 3 and 12 months, with 10% of participants meeting diagnostic criteria for each disorder at 12 months19. Another prospective, nationwide, multi-center study of 17 centers found that 27% of patients with TBI met the prerequisite number symptoms for a DSM-IV diagnosis of major depressive disorder20.
Another study of clinical depression involving people with multiple sclerosis used data from a large-scale national survey conducted in Canada, the Canadian Community Health Survey (CCHS). The analysis included 115,071 CCHS subjects who were 18 years or older at the time of data collection and was based on self-reported diagnoses of MS and employed a brief predictive interview for major depression, the Composite International Diagnostic Interview Short Form for Major Depression. The 12-month period prevalence of major depression was estimated in subjects with and without MS and with and without other long-term medical conditions. The prevalence of major depression was elevated in persons with MS relative to those without MS and those reporting other conditions; major depression prevalence in MS was high at 25.7% (95% CI 15.6 to 35.7)21.
Later in life, depression and anxiety disorders are associated with excess disability. Studies show disability to be a risk factor for depression. One study of older male veterans receiving primary care showed pain-related disability as a common occurrence among this population. Depressive symptoms and pain intensity are associated with pain-related disability and represent targets for intervention among older persons in pain.22
Another study examined the reciprocal effects between depressive symptoms and functional disability and their temporal character in a community-based cohort of 753 older people with physical limitations who were assessed at yearly intervals. A strong association was found between functional disability and depressive symptoms in older people. According to this study, some studies attribute this association to the disabling effects of depression, while others to the depressogenic effects of physical health-related disability. The researchers suggest that to improve quality of life in elderly adults, treatment should target disability when it is new and depression when it is persistent23.
It is very important to consider the impact of major depressive disorder, since it is the leading cause of disability in the U.S. and established market economies worldwide. It affects approximately 9.9 million American adults, or about 5.0 percent of the U.S. population age 18 and older in a given year. Treating it correctly can be a matter of life or death—more than 90 percent of people who kill themselves have a diagnosable mental disorder, commonly a depressive disorder or a substance abuse disorder24.
As well, depression in persons with disabilities affects productivity and quality of life; according to one survey, persons with disabilities and major depression are less likely to work than other persons with disabilities25. One study of survivors of traumatic brain injury (TBI) over a 3-year period after injury found that survivors with depression had significantly lower life satisfaction than the no depression group at 24-, 48- and 60-month interviews26. Due to the prevalence of depressive symptoms and major depressive disorder among people with disabilities and its impact on quality of life, it is important to study effective ways of treating it in this population and to ensure access to treatment.
1 National Institute of Mental Health. The Numbers Count: Mental Disorders in America: a summary of statistics describing the prevalence of mental disorders in America. 2001http://www.nimh.nih.gov/publicat/numbers.cfm
2 American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition (DSM-IV). 1994
3 Radloff, LS. The CES-D scale: A self-report depression scale for research in the general population. Applied Psychological Measurement. 1977 (1):385-401
4 Chwastiak L, Ehde D, Gibbons L, Sullivan M, Bowen J, Kraft G. Depressive symptoms and severity of illness in multiple sclerosis: Epidemiologic study of a large community sample. American Journal of Psychiatry. 2002 Nov;159(11):1862-1868 U Washington, Multiple Sclerosis Rehabilitation Research and Training Center, Seattle, WA, USA.
5 Rangel L, Garralda ME, Hall A, Woodham S. Psychiatric adjustment in chronic fatigue syndrome of childhood and in juvenile idiopathic arthritis. Psychol Med. 2003 Feb;33(2):289-97. Academic Unit of Child and Adolescent Psychiatry, Faculty of Medicine, Imperial College at St Mary’s Campus, London. Comment in: Psychol Med. 2003 Feb;33(2):197-201.
6 Grey M, Whittemore R, Tamborlane W. Depression in type 1 diabetes in children: natural history and correlates. J Psychosom Res. 2002 Oct;53(4):907-11. Yale School of Nursing, 100 Church Street South, New Haven, CT 06519, USA.
7 Kashikar-Zuck S, Goldschneider KR, Powers SW, Vaught MH, Hershey AD. Depression and functional disability in chronic pediatric pain. Clin J Pain. 2001 Dec;17(4):341-9 Children’s Hospital Medical Center, and Department of Pediatrics, University of Cincinnati College of Medicine, Ohio 45229, USA.
8 Sandstrom MJ, Schanberg LE. Peer rejection, social behavior, and psychological adjustment in children with juvenile rheumatic disease. J Pediatr Psychol. 2004 Jan-Feb;29(1):29-34 Department of Psychology, Williams College, Williamstown, MA 01267, USA.firstname.lastname@example.org
9 Edwards TC, Patrick DL, Topolski TD. Quality of life of adolescents with perceived disabilities. J Pediatr Psychol. 2003 Jun;28(4):233-41 University of Washington, Center for Disability Policy and Research, Seattle, Washington 98103-8652, USA. email@example.com
10 North Carolina Office of Disability and Health. Growing Up With Spina Bifida booklet.
11 Massachusetts Department of Health. November 2001. A Profile of Massachusetts Adults with Disabilities, 1998-2000—Results from the Behavioral Risk Factor Surveillance System
12 New Mexico Department of Health. Revised—April, 2002. Disability in New Mexico—a Report Based on the State of New Mexico Behavioral Risk Factor Surveillance System Surveys of 1998-2000.
13 North Carolina Division of Public Health. May, 2001. Health Risks Among North Carolina Adults: 1999—A Report from the Behavioral Risk Factor Surveillance System.
14 Rhode Island Department of Health. June, 2000. Rhode Island Disability Chartbook—Findings from an Analysis of the 1998 Rhode Island Behavioral Risk Factor Surveillance System.
15 Washington State Department of Health. January 2001. Disability in Washington State.
16 McBrien JA. J Intellect Disabil Res. 2003 Jan;47(Pt 1):1-13. Assessment and diagnosis of depression in people with intellectual disability. Plymouth Primary Care Trust/University of Plymouth, LDS, Westbourne Unit, Scott Hospital, Plymouth PL2 2PQ, UK. firstname.lastname@example.org
17 Cuthill FM, Espie CA, Cooper SA. Development and psychometric properties of the Glasgow Depression Scale for people with a Learning Disability. Individual and career supplement versions. Br J Psychiatry. 2003 Apr;182:347-53. University of Glasgow, Scotland, UK.
18 Buchanan RJ, Wang S, Tai-Seale M, Ju H. Analyses of nursing home residents with multiple sclerosis and depression using the Minimum Data Set. Mult Scler. 2003 Mar;9(2):171-88. Department of Health Policy and Management, School of Rural Public Health, The Texas A&M University System Health Science Center, College Station, TX 77843-1266, USA.email@example.com
19 O’Donnell ML, Creamer M, Pattison P, Atkin C. Psychiatric morbidity following injury. Am J Psychiatry. 2004 Mar;161(3):507-14. Department of Psychology, University of Melbourne, Parkville, Australia. firstname.lastname@example.org
20 Seel RT, Kreutzer JS, Rosenthal M, Hammond FM, Corrigan JD, Black K. Depression after traumatic brain injury: a National Institute on Disability and Rehabilitation Research Model Systems multicenter investigation. Arch Phys Med Rehabil. 2003 Feb;84(2):177-84. Defense and Veterans Brain Injury Center, McGuire Veterans Administration Medical Center, Richmond, VA, USA.
21 Patten SB, Beck CA, Williams JV, Barbui C, Metz LM. Major depression in multiple sclerosis: a population-based perspective. Neurology. 2003 Dec 9;61(11):1524-7 Department of Community Health Sciences, University of Calgary, Alberta, Canada. email@example.com
22 Reid MC, Guo Z, Towle VR, Kerns RD, Concato J. Pain-related disability among older male veterans receiving primary care. Clinical Epidemiology Unit, VA Connecticut Healthcare System. West Haven 06516, USA. firstname.lastname@example.org
23 Ormel J, Rijsdijk FV, Sullivan M, van Sonderen E, Kempen GI. Temporal and reciprocal relationship between IADL/ADL disability and depressive symptoms in late life. J Gerontol B Psychol Sci Soc Sci. 2002 Jul;57(4):P338-47. Department of Psychiatry, University of Groningen, The Netherlands. email@example.com
24 National Institute of Mental Health. The Numbers Count: Mental Disorders in America: a summary of statistics describing the prevalence of mental disorders in America. 2001
25 Zwerling C, Whitten PS, Sprince NL, Davis CS, Wallace RB, Blanck PD, Heeringa SG. Workforce participation by persons with disabilities: the National Health Interview Survey Disability Supplement, 1994 to 1995. J Occup Environ Med. 2002 Apr;44(4):358-64. University of Iowa, College of Public Health, 100 Oakdale Campus, #126 IREH, Iowa City, IA 52242-5000, USA. CZwerling@mail.public-health.uiowa.edu
26 Underhill AT, Lobello SG, Stroud TP, Terry KS, Devivo MJ, Fine PR. Depression and life satisfaction in patients with traumatic brain injury: a longitudinal study. Brain Inj. 2003 Nov;17(11):973-82. Injury Control Research Center, University of Alabama at Birmingham School of Medicine, Birmingham, AL 34294, USA. firstname.lastname@example.org