Common mental disorders among patients with diabetes in a secondary care facility: nature, prevalence, and explanatory models

INTRODUCTION

Diabetes mellitus (DM) has been described as a growing epidemic by the World Health Organization with the majority of those affected living in low-and middle-income countries.¹ The prevalence has been steadily increasing, attributable to a variety of factors including genetics and lifestyle. Diabetes and psychiatric disorders often co-exist. The relationship between the two is considered to be bidirectional, as DM can increase the risk of developing certain mental disorders while the presence of a psychiatric disorder is associated with greater incidence and prevalence of DM.²

CMDs such as depression and anxiety have been found to be more prevalent among persons with DM as compared to the general population.³ Patients may experience adjustment difficulties and distress related to the challenges of the daily management of the illness and the threat of complications.⁴ Depressive disorders are two and three times more common in people with type 2 and type 1 diabetes respectively in comparison with the general population.⁵ The risk of anxiety disorders is also higher than among people without DM.⁶ Conversely, metabolic side-effects of some medicines used in the treatment of psychiatric disorders can lead to the development or worsening, of diabetes.⁷ The mechanisms thought to underly the association of DM with psychiatric disorders are multifactorial and include genetic, biological (hypothalamic-pituitary-adrenal axis activation, inflammation, oxidative stress, insulin sensitivity), behavioural (lifestyle and dietary habits), psychosocial (stress, adherence to treatment) and disease-specific factors (antidepressant and antipsychotic medication use).⁸ Risk factors for the development of CMDs in individuals with diabetes include female gender, poverty, poor glycaemic control, longer duration of diabetes and presence of long-term complications.⁹

The presence of comorbid mental disorders can interfere with adherence to diabetes care regimens resulting in unhealthy habits, irregular monitoring of blood sugar, missing medication and skipping doctor’s appointments, leading to worse health outcomes, a poor quality of life and premature mortality. Beliefs and conceptualization regarding the illness also influence treatment adherence and disease related morbidity. Therefore, eliciting explanatory models (EMs) of illness from patients can help the physician better understand their attitudes towards the illness and its treatment. The nature of explanatory models varies and can include biomedical explanations such as heredity, obesity, poor diet and lack of exercise, as well as folk or traditional models which reflect religious and cultural influences.^10,11 Multiple, and even contradictory EMs, may be held simultaneously.¹² Differences in explanatory models between the patient and physician have been identified as an important reason for non-compliance with prescribed treatment.¹³

Despite their high prevalence in medical settings and the community, co-morbid psychiatric disorders in diabetics are not often recognised or adequately treated.¹⁴ This study aimed to explore the prevalence and nature of CMDs present in people with diabetes and their explanatory models of illness. This can help plan care programs that effectively address some of the challenges associated with living with diabetes.

METHODS

Study design and setting

This cross-sectional study was carried out in a secondary care hospital catering primarily to the rural population around a town in the state of Tamil Nadu, southern India, specifically focused on individuals residing in 82 villages and 175 tribal hamlets.

Sample

Patients who presented to the diabetic clinic at the hospital were contacted for possible recruitment to the study using systematic sampling. Those above the age of 18 years who spoke Tamil were considered eligible to take part, while subjects with severe language, hearing, or cognitive impairment were excluded. Informed consent was obtained from the participants. Patients were recruited over a period of 12 months from February 2019 and were interviewed at a single point in time.

Assessment

The revised clinical interview schedule (CIS-R) was used to assess for CMDs. This standardized semi-structured interview assesses the mental state of individuals with non-psychotic disorders and provides a symptom profile and a total score that enables the patient to be classed as a case (scoring 12 or more) or non-case. It has been shown to have high inter-rater reliability and has been translated into several Indian languages. The Tamil version of the interview was used for this study.¹⁵ Beliefs about illness were recorded using the SEMI.¹⁶ It explores the patient's perspectives regarding the nature of the illness, its perceived causes and impact, and help-seeking behaviour. It is semi-structured in design with open-ended questions along with probes to elicit concepts. A brief instrument with well-established face and content validity, it has been translated into many different languages. The Tamil version was used in this study.¹⁷ Demographic and clinical details of the patient were recorded in a specifically designed proforma. All interviews were conducted by a single researcher (SSS).

Sample size estimation and data analysis

A sample size of 154 was obtained using the formula 4pq/d², where p denotes the estimated prevalence of CMD in patients with diabetes (45%), q=(100-p), and d the precision, taken as 8. The statistical software SPSS for Windows (version 16) was used to analyse the data. Mean and standard deviation were employed to describe continuous variables, while frequency distributions were obtained for categorical data. The chi-square test and the student’s t test were used to assess the significance of associations for categorical and continuous variables respectively. Logistic regression was employed as multivariate statistics to adjust for confounders.

Ethical considerations

The study protocol was approved by the Institutional Review Board and Ethics Committee (IRB Min No. 11707 dt 03/12/2018).

RESULTS

A total of 201 subjects who fulfilled eligibility criteria were contacted for possible recruitment to the study, and 170 subjects (84.6%) consented to participate. There was no statistical difference in the age and gender of those who consented and those who did not. The sociodemographic and clinical characteristics are documented in Table 1. The majority of the sample were female, married, could read and write and were from a rural, low socioeconomic background. About half the participants were wage earners. The average distance travelled to reach the hospital was 4.45 kms and the mean cost incurred for travel was 5.56 INR. The majority of the participants had type 2 DM and the mean age of onset was 50.78 years. Most were on one or more oral hypoglycaemic agents and a smaller group was on insulin. The HbA1c was available for 42 out of the total sample and the mean value was 7.78%. Comorbidity was common (90.6%), mostly hypertension (80.6%) and dyslipidemia (72.9%), 17.1% of the sample had been on psychiatric treatment in the past. Twenty-five (14.7 %) of the 170 patients interviewed scored 12 or more on the CIS- R, satisfying criteria for a common mental disorder. Using items from the CIS-R, algorithms were constructed for different psychiatric diagnoses based on ICD-10-primary care version criteria for these 25 participants; anxiety was the most common disorder (10%), followed by depression and neurasthenia (2.35% each).

Table 2 records the factors associated with CMDs. On bivariate analysis, presence of CMD was associated with female gender (p=0.03), longer duration of diabetes (p=0.016) and treatment (p=0.02), use of insulin (p=0.001) as compared to oral hypoglycaemics alone and past history of treatment for psychiatric illness (p<0.001). These remained significant on adjusting for age in logistic regression. The following factors were not significantly associated with presence of CMD: age, marital status, religion, residence, income and debt, literacy and education, distance and cost of travel to a hospital, type of DM, drug compliance, presence of comorbid illnesses, blood pressure, blood sugar and lipid levels, diet, exercise, alcohol and nicotine use, perceived social support, and family history of DM.

The responses to the SEMI are listed in Table 3. An unhealthy diet (35.9%), heredity (28.2%) and stress (12.9%) were common attributions for the development of the disease. Twenty percent of the participants said they did not know the cause while two participants felt their problems could be a result of punishment from God. Many perceived their illness to be moderately (72.9 %) or very (17.1 %) serious, and the majority (75%) reported a fear of physical complications of the disease. All domains of life were affected by the illness, work (65.9%) being the most commonly mentioned. Almost half (45.9%) responded that they were emotionally affected by the illness and cited financial difficulties (32.1%), physical symptoms (32.1%) and the perception of being a burden to others (33.3%) as the cause. While all expected to receive help from medical professionals, dietary restrictions and exercise, some participants also believed that religion (24%) and traditional healers (1.2%) could help. All the patients had approached other sources for advice regarding diabetes and two were taking traditional medication in addition to those prescribed in the hospital.

Presence of common mental disorder was significantly associated with patient’s admission of being emotionally affected by illness (χ²=25.10; df=l; p<0.001) and belief that illness was a punishment from God (χ²=11.73; df=l; p=0.021). Association between psychiatric morbidity and a perception that the illness had a chronic course showed a trend towards statistical significance (χ²=6.57; df=l; p=0.057). There were no significant associations between presence of CMD and perceived seriousness of illness or expectation of care from different sources.

CISR: Clinical Interview Schedule-Revised; SD: standard deviation; CI: confidence interval.

(* Multiple responses)

DISCUSSION

In addition to the effects on the physical health of patients, living with diabetes can have a significant impact on the emotional health of the individual. This study attempted to study the prevalence and factors associated with CMDs among patients with diabetes and their explanatory models of illness in an out-patient secondary care hospital setting.

The prevalence of CMD in this population of diabetic individuals was 14.7%, lower than that reported in studies by Das-Munshi (21.6%) and Claro (43%).^3,18 Variations in reported prevalence rates may be attributable to differences in study settings and populations, assessment methods, methods of classifying CMDs as symptoms or syndromes, type of diabetes and sample size.¹⁹ Anxiety was the most common disorder identified (10%) in the present study. In a meta-analysis of patients with diabetes, prevalence of generalized anxiety disorder was 14% and symptoms of anxiety was 40%. ²⁰ In a German sample of diabetic patients, the prevalence of anxiety disorders was 5.9%, with an additional 19.3% reporting some anxiety symptoms.²¹ Clinicians should therefore be alert to the possibility of syndromal, as well as subsyndromal anxiety in persons with diabetes. Depression has been the most studied of the mental disorders associated with diabetes and a meta-analysis reported the prevalence in type 2 diabetes to range from 1.8% to 88%.²² This study found the prevalence of depression to be 2.35%. While many researchers have reported a greater prevalence of depression in diabetic patients, even up to twice that of the general population, others failed to find a significant difference in the prevalence of depression between diabetic and non-diabetic individuals.^21,23

Female gender was found to be associated with common mental disorder; this is a finding reported by several researchers. Deischinger et al observed the gender gap for depression in diabetes to be even more pronounced than among non-diabetic controls, suggesting that women with diabetes, especially those at a high-risk due to obesity or cardiovascular disease, be carefully monitored for psychiatric morbidity.²⁴ Longer duration of illness was associated with psychiatric morbidity, similar to that reported in research from other countries.²⁵ In a study of older men, the association between duration of diabetes and risk of depression increased in the first few years, then declined-possibly due to acceptance of the illness and the effects of treatment, and then increased again in later years-secondary to the increase in complications, comorbidities and frailty.²⁶ A negative appraisal of insulin therapy has been noted among many people with diabetes, associated with poor emotional well-being and lower diabetes related self-efficacy. This has been attributed to fear of injections or concerns regarding potential complications from insulin.²⁷ In the present study, being on insulin in contrast to OHAs alone, was associated with psychiatric comorbidity. Though not replicated in this study, other factors that have been reported to be associated with depressive symptoms in persons with diabetes include older age, lower socioeconomic status, inadequate social support and diabetes related complications.⁹

Comorbid anxiety or depression in diabetes interferes with compliance with self-care regimens resulting in poorer glycaemic control and a negative impact on the quality of life.²¹ Therefore physicians need to routinely screen their patients with diabetes for these syndromes, as well as non-syndrome symptoms of mental distress which may be even more common than full-fledged mental disorders. Acknowledging patients’ distress, providing them adequate time to discuss their concerns, teaching them techniques to correct negative thought patterns and breathing and muscular relaxation exercises to reduce anxiety are useful interventions.²⁸ Selective serotonin re-uptake inhibitors, such as sertraline, fluoxetine and escitalopram are useful in the treatment of depressive and anxiety disorders and also have a favourable effect on glycaemic control; tricyclic antidepressants, paroxetine and mirtazapine are less suitable as they induce significant weight gain.²⁹

An explanatory model of illness or the way a person makes sense of his/her ailment can significantly influence a patient’s attitude towards treatment compliance, clinical outcome and quality of life. Eliciting the belief systems and explanatory models of patients in routine clinical practice helps medical professionals gain a better understanding of their subjective experience of illness.³⁰ Most participants in the study held biomedical models of illness, though some simultaneously held causative explanations such as punishment from God, and treatment expectations from traditional and religious interventions. In studies among Mexican-American and Ghanaian patients with diabetes, the illness was thought to be caused by experiencing strong emotions, supernatural sources such as witchcraft, sorcery or evil forces, as well as heredity, stress, obesity, poor diet and lack of exercise.^10,31 Similarly, combined biomedical and traditional belief systems were reported in studies involving Hispanic and Ethiopian patients with diabetes.^11,12 Cultural differences in attributing responsibility and blame for developing the disease were noted in research from Britain; while south-east Asians highlighted their life circumstances in accounting for diabetes thus externalizing the cause, white respondents tended to emphasize the role of their own lifestyle choices and personal failings. Individuals who see themselves as responsible for maintaining their physical health have been shown to be more likely to take steps to improve their health and have good adherence to a medical regimen.³² Being uncertain about the cause of DM and a having a perception that one had little or no control over it was associated with seeking religious healing and traditional medicine in addition to, or instead of, the biomedical methods. Non-medical, external explanations and supernatural causes are often used when people are trying to cope with chronic illness and are asking questions that go beyond the workings of mechanical and biological causes.^33,34 The fatalistic view that diabetes was a result of supernatural punishment for previous or current sinful behaviour was associated with the presence of a common mental disorder in this study. While this suggests that some aspects of religion may have negative consequences for mental health, religiosity can also have positive effects by helping patients reframe their medical condition as something that helps them gain pardon for sins.³⁵ While medical staff view diabetes principally as a biological problem, patients highlight difficulties in the different domains of their daily lives.¹³ In the present study as well, participants expressed concerns about the deleterious effects of DM on many non-health domains of life such as social interactions, relationships, finances, mobility and ability to carry out daily activities and duties.^12,13 To improve functioning and quality of life, healthcare professionals need to elicit patients’ specific areas of concern and work with them collaboratively to plan interventions tailored to their individual needs.³⁶ The perception that the illness had a chronic course was associated with case-ness on CISR with a p value approaching significance. Patients’ beliefs regarding the nature, course and consequences of their illness have been shown to significantly affect their psychological health, perhaps even more than the actual status of the medical disease.³⁷

Several research studies including the present one note that many patients said they were not aware of the cause of DM.^11,12 This highlights the need for health care professionals to actively engage patients in diabetes education to ensure a good clinical outcome.³⁸ Providing adequate health information will ensure a better understanding of the condition and improve the patient’s own ability and confidence to manage it. In patients who are ambivalent about making the necessary lifestyle changes of regular physical exercise, diet modification, sleep hygiene and avoidance of substance use, pointing out the discrepancy between current behaviour and his or her health-related goals, can help to increase motivation for change.³⁹ Engaging the patient’s family and eliciting their support also helps to minimize distress.

CONCLUSION

Depression and anxiety are a risk factor as well as a complication of diabetes. Care teams need to be sensitive to patients’ experiences of their illness and be aware of the individual patient’s understanding of the illness and its management. A comprehensive diabetes education protocol keeping in mind the local and individual contexts, and screening for the presence of common psychiatric problems should be incorporated into routine clinical practise. Lifestyle modification along with psychological interventions and appropriate weight neutral pharmacological agents can improve both glycaemic control and depressive symptoms.

Funding: Funding sources by Fluid Research Grant No. 22Z651, from Christian Medical College, Vellore.

Conflict of interest: None declared

Ethical approval: The study was approved by the Institutional Ethics Committee IRB Min No. 11707 dt 03/12/2018).

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