Anger and mental health in type 2 diabetes

Diabetes and Primary Care, Summer, 2004 by Andrew Kolbasovsky

Introduction

Previous qualitative studies have identified anger as an important issue for people with diabetes yet few quantitative studies have addressed this topic. In this study, participants with type 2 diabetes had greater anger than participants without diabetes. There was a significant association between diabetes status and anger (p < 0.01). Our findings suggest that members of the diabetes treatment team need to assess and address issues of anger, which may affect the physical as well as the mental health of people with diabetes.

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Diabetes has been associated with an elevated rate of psychological symptoms. The increased prevalence of depressive symptoms experienced by people with diabetes has been well documented (Anderson et al, 2001; Snoek, 2002). Anger, another psychological symptom theorised to be more prevalent in people with diabetes (Cox, 1994; Lewis, 1998), has received much less attention in the literature and studies addressing anger have relied on qualitative designs.

In a study of 14 people with type 2 diabetes, McCord and Brandeburg (1995) noted that many expressed strong feelings of frustration and anger. Similar results were obtained in open-ended interviews of 22 people with diabetes in Korea (Choe et al, 2001) and Snoek (2002) noted that misconceptions about having to start insulin treatment are often associated with negative emotions such as anger and fear. The possible connection between anger and diabetes is particularly important for clinicians who work in primary care, because chronic anger has been linked with increased risk of cardiovascular disease (Chang et al, 2002; Sirois and Burg, 2003), hypertension (Rutledge and Hogan, 2002), and elevated cholesterol (Waldstein et al, 1990).

One particular group of people with diabetes who may be at the highest risk of elevated anger are people with diabetes who have a mental health condition as Posternak and Zimmerman (2002) found that anger is a prominent emotion for people receiving outpatient psychiatric care.

Hypotheses

It is hypothesised that people who are treated for type 2 diabetes in a primary care setting and who are also receiving care at an outpatient mental health centre will report significantly greater anger than people who are treated at the same mental health centre and who do not have diabetes.

It is further hypothesised that diabetes status will be more strongly associated with anger than age, gender, mental health diagnosis category, type of insurance, or presence of co-occurring medical conditions other than diabetes.

Methods

A convenience sample of 95 adults (aged [greater than or equal to]21 years) receiving treatment from a therapist (nurse, social worker, or psychologist) and/or psychiatrist at an outpatient mental health centre was identified. Participants completed a background information sheet and the Novaco Anger Inventory (short form). A total of 95 people were invited to participate in the study and all agreed to complete the questionnaires. Of the 95 participants, 39 reported that they received primary care treatment for type 2 diabetes and 56 reported that they did not have diabetes. The ages of the participants with type 2 diabetes ranged from 42-72 years, with an average age of 55.51 years and a standard deviation of 8.53. The ages of the participants without diabetes ranged from 21-80 years, with an average age of 47.95 years and a standard deviation of 14.43. Further data of participant characteristics are presented in Table 1.

Instruments

The Novaco Anger Inventory (NAI) short form (Novaco, 1975), a valid, reliable, conveniently administered and well-known tool designed to measure the degree of provocation or anger people would feel if placed in certain situations, was administered to assess anger level. The NAI-25 contains 25 items, each consisting of a situation. A rating is given for how angry or annoyed the rater would feel in each situation. Responses range from 'very little' to 'very much' on a 5-point scale.

Background information was obtained from a survey in which participants indicated their diabetes status, as well as any medical conditions other than diabetes, age, and gender.

Procedure

Each participant was recruited by one of eight mental health treatment providers at the mental health centre. The purpose of the study and its requirements were explained and each person was invited to participate. After providing informed consent to take part in the study, participants were asked to complete the Novaco Anger Inventory (short form) and a brief background information sheet. A mental health diagnosis was obtained using the diagnostic and statistical manual of mental disorders (DSM-IV [American Psychiatric Association, 1994]). The confirmation of the diagnosis of type 2 diabetes was obtained by chart review.

Statistical analysis

A cross-sectional study was conducted to evaluate the association between having type 2 diabetes and reported anger. Age, gender, type of insurance, DSM-IV diagnostic category (depressive disorder, anxiety disorder, adjustment disorder, psychotic disorder, bipolar disorder, developmental disorder) and whether or not the person had a medical diagnosis other than diabetes were considered possible confounding variables that may be associated with anger scores. Chi-square analyses and a t-test for independent samples were conducted as appropriate, to determine whether any of these variables were significantly associated with anger scores. In order to control for the effect of any variables found to be associated with anger, each significant variable was included in the hierarchical regression model along with diabetes status.