INVITED COMMENTARY

Diabetes and DepressionCathy E. Lloyd, PhD

AddressThe Open University, School of Health and Social Welfare, Walton Hall, Milton Keynes, MK7 6AA, UK.E-mail: C.E.Lloyd@open.ac.ukCurrent Diabetes Reports 2002, 2:465466Current Science Inc. ISSN 1534-4827Copyright 2002 by Current Science Inc.

Clinical and research experience tell us that diabeteshas both a daily and long-term impact on individuals,both physiologically and in terms of the psychosocialeffects of the disease. These can include effects on mentalhealth, for example, anxiety and depression, self-esteem,self-health care, day-to-day living activities, and overallquality of life [1].

Compared with the general population, individualswith diabetes have a much greater risk of developing symp-toms of depression, although the reasons for this remainunclear. International studies have estimated that theprevalence rate of depression may be at least twice therate in the general population [2]. Clinical depressionin individuals with diabetes may recur more frequently,episodes may last longer, and the long-term recovery ratemay also be much lower. This increased risk for depressionis thought to be similar in individuals with type 1 andin those with type 2 diabetes, although, like the general(nondiabetic) population, women are more likely toreport symptoms of depression compared with men [2].

Depression may be linked to glycemic control, eitherthrough hormonal dysregulation, or more likely via thenegative effect on diabetes self-care behavior, includinglower levels of physical activity, increased smoking, aswell as poorer blood glucose monitoring. In a recent meta-analysis, Lustman et al. [3] observed that depression wasassociated with hyperglycemia in individuals with eithertype 1 or type 2 diabetes, although the directional natureof this relationship was still unclear. It is now well estab-lished that poor glycemic control is associated with anincreased risk for developing the complications of diabe-tes, including diabetic retinopathy, peripheral neuropathy,and renal problems. Risk of heart disease and stroke is alsoincreased, but these and other diabetes complications maybe further affected by depressive symptomatology [4].

Whether psychological distress increases the riskof developing diabetes or its complications, or whetherdiabetes or diabetes complications increases the risk of

they have important consequences for both the individualwith diabetes and the health care professionals involved intheir care. Despite its higher prevalence, depression indiabetes seems poorly recognized. US studies estimatethat only one third of people with diabetes and majordepression are identified and treated [5]. There may beboth under-reporting and underdiagnosing of depressivedisorders in individuals with diabetes, because psycho-logical problems are often seen as secondary to thediabetes by both patient and physician.

Patients may not consider their depressed mood to beof relevance to their diabetes treatment, have no knowl-edge or low expectations of therapy effectiveness, or maybe reluctant to discuss their mood disorder with theirdoctor [5]. Anecdotally, we have observed that in theUnited Kingdom it is often seen as inappropriate to reportany kind of emotional or psychological problem,with these types of symptoms taking second place to thephysical symptoms of diabetes during clinical care. In onestudy, many individuals reported that this was the firsttime they had been able to describe how they were feelingwithout fear of stigma or lack of understanding [1].

There may be a confounding of symptoms of diabeteswith symptoms of depression (eg, fatigue, changes in sleep,weight, and appetite), which may lead to underdiagnosisof depression. However, although there may be someoverlap between the symptoms of depression and some ofthe physiologic symptoms of diabetes, these symptoms donot significantly compromise the sensitivity or the validityof the diagnosis of depression, either when using criteria-based diagnostic symptoms (ie, Diagnostic and StatisticalManual IV diagnoses) or when using screening toolssuch as the Beck Depression Inventory. Case-findinginstruments, such as the Center for Epidemiologic StudiesDepression scale, have also proven to be effective inscreening for depression in primary care settings, and to besuitable for use in people with diabetes.

Research has shown that some screening toolscan easily be used in a clinical setting by healthcare professionals and their patients [1]. In one study, ashort 14-item questionnaire was used and 96% ofpatients who were approached agreed to complete theform [1]. In the same study, one third of respondentsreported that they were interested in receiving counselingor psychotherapy; these individuals were significantlymore likely to report symptoms of depression or anxietydepression, or whether these two are merely coincidental, at the same time.

466 Invited Commentary

It is known that those patients with diabetes are morelikely to suffer from chronic depressive episodes or experi-ence a relapse [6]. Depression in individuals with diabetesmay be especially severe due to their interaction at theneuroendocrine level [6]. However, not all individualswith diabetes suffer from clinically recognized levels ofdepression; some may experience lower levels of mooddisturbance, or mild levels of depressive symptomatology[1]. These levels of depressive symptomatology arenonetheless important; a recent report from the PittsburghEpidemiology of Diabetes Complications Study showedthat even relatively low levels of symptomatologywere associated with an increased risk of developing heartdisease [7]. Although literature on the treatment ofdepression in people with diabetes is still scarce, there issome evidence that cognitive behavior therapy and anti-depressant medication are as effective in those withdiabetes as in those without diabetes, with additionalbeneficial effects on glycemic control [6].

Given the high prevalence of depressive symptomatol-ogy in individuals with diabetes, further research is clearlywarranted to establish the reasons why this is the case andthe factors associated with this. International comparisonsare useful because they may highlight both similarities anddifferences in the rates of psychological morbidity as wellas suggest possible differences in potential explanatoryvariables. Important questions include the following:1) Why is depression more common in individuals withdiabetes? 2) What factors are associated with this highprevalence? 3) Why are some individuals diagnosedwhereas other are not, and what happens to those who arediagnosed with depression? 4) What factors are associatedwith its remission? Under the auspices of the PsychosocialAspects of Diabetes Study Group, a group of Europeanresearchers have developed a protocol that aims toinvestigate these important questions. Countries as diverseas the United Kingdom, Holland, Germany, Croatia, andSlovenia are currently involved in this research initiative,aptly named the European Depression in DiabetesStudy Group.

In summary, depression and depressive symptomatol-ogy are both more common in those with diabetescompared to those without, but can be treated effectivelyin many cases. Depression may have a detrimental effecton glycemic control; however, not all those who aredepressed have high blood sugar levels, and many diabeticpatients who are depressed manage their diabetes well. It isimportant for the health professional working with thediabetic patient to recognize that diabetes and depressionmay go together but that they are separate conditionsboth of which must be treated aggressively in order tomaximize the benefits to the person with diabetes.

Recently, there has been a surge of interest in psycho-logical and psychosocial aspects of chronic disease, andresearch in depression and diabetes has gained greaterrecognition. This has been in light of the evidence thatdoes exist of the serious impact of psychological problemson individuals with chronic conditions such as diabetes,their impact on day-to-day living, and the high costs toboth the individual and society.

References1. Lloyd CE, Dyer PH, Barnett AH: Prevalence of symptoms of

depression and anxiety in a diabetes clinic population. Diabet Med 2000, 17:198202.

2. Anderson RJ, Freedland KE, Clouse RE, Lustman PJ: The preva-lence of comorbid depression in adults with diabetes. Diabetes Care 2001, 24:10691078.

3. Lustman PJ, Anderson RJ, Freedland KE, et al.: Depression and poor glycemic control: a meta-analytic review of the literature. Diabetes Care 2000, 23:934942.

4. De Groot M, Anderson RJ, Freedland KE, et al.: Association of depression and diabetes complications: a meta-analysis. Psychosom Med 2001, 63:619630.

5. Lustman PJ, Clouse RE, Alrakawi A, et al.: Treatment of major depression in adults with diabetes: a primary care perspective. Clin Diabetes 1997, 15:122126.

6. Rubin RR, Peyrot M: Psychological issues and treatments for people with diabetes. J Clin Psychol 2001, 57:457478.

7. Kinder LS, Kamarck TW, Baum A, Orchard TJ: Depressive symptomatology and coronary heart disease in type 1 diabetes mellitus: a study of possible mechanisms. Health Psychol 2002, in press.

Diabetes and DepressionDiabetes and DepressionCathyCathyE.Lloyd,PhD

AddressAddressThe Open University,The Open University,School of Health and Social Welfare,Walton Hall,Milton Keynes,MK7 6AA,UK.E-mail: C.E.Lloyd@open.ac.uk

Current Diabetes ReportsCurrent Diabetes Reports2002,2:465465

Current Science Inc. ISSNCopyright 2002 by Current Science Inc.

Clinical and research experience tell us that diabetes hasboth a daily and long-term impact on i...Clinical and research experience tell us that diabetes hasboth a daily and long-term impact on i...Compared with the general population, individuals with diabetes have a much greater risk of devel...Depression may be linked to glycemic control, either through hormonal dysregulation, or more like...Whether psychological distress increases the risk ofdeveloping diabetes or its complications, or...Patients may not consider their depressed mood to be of relevance to their diabetes treatment, ha...There may be a confounding of symptoms of diabetes with symptoms of depression (Research has shown that some screening tools caneasily be used in a clinical setting by health c...It is known that those patients with diabetes are more likely to suffer from chronic depressive e...Given the high prevalence of depressive symptomatology in individuals with diabetes, further rese...In summary, depression and depressive symptomatology are both more common in those with diabetes ...Recently, there has been a surge of interest in psychological and psychosocial aspects of chronic...

ReferencesReferences1. Lloyd1. Lloyd1. LloydCE,DyerPH,BarnettAH:Prevalence of symptoms of depression and anxiety in a diabetes clinic population.Diabet Med2000,17:198202.

2. Anderson2. Anderson2. AndersonRJ,FreedlandKE,ClouseRE,LustmanPJ:The prevalence of comorbid depression in adults with diabetes.Diabetes Care2001,24:10691078.

3. Lustman3. Lustman3. LustmanPJ,AndersonRJ,FreedlandKE,et al.:Depression and poor glycemic control: a meta-analytic review of the literature.Diabetes Care2000,23:934942.

4. De Groot4. De Groot4. De GrootM,AndersonRJ,FreedlandKE,et al.:Association of depression and diabetes complications: a meta-analysis.Psychosom Med2001,63:619630.

5. Lustman5. Lustman5. LustmanPJ,ClouseRE,AlrakawiA,et al.:Treatment of major depression in adults with diabetes: a primary care perspective.Clin Diabetes1997,15:122126.

6. Rubin6. Rubin6. RubinRR,PeyrotM:Psychological issues and treatments for people with diabetes.J Clin Psychol2001,57:457478.

7. Kinder7. Kinder7. KinderLS,KamarckTW,BaumA,OrchardTJ:Depressive symptomatology and coronary heart disease in type 1 diabetes mellitus: a study of poss...Health Psychol2002,in press.