The potential role of Type D personality in people with diabetes. with co-morbid depression

Transcription

1 Running head: THE ROLE OF TYPE D PERSONALITY IN PEOPLE WITH DEPRESSION The potential role of Type D personality in people with diabetes with co-morbid depression Neruthiga Sellathuri Tilburg University Tilburg University, Department of Medical and Clinical Psychology Author: Neruthiga Sellathuri, BSc. ANR: Supervisors: Prof. dr. F. Pouwer and dr. M. Hendricx (second assessor) Date: 20 th of November 16

2 Abstract Background: Depression is common in people with diabetes but the risk factors for depression are still unclear. Persons with Type D personality experience a lot of negative emotions but do not express this. The aim of this study is to examine the associations between Type D personality, negative affect (NA) and social inhibition (SI) and risk of comorbid depression in people with diabetes. It was expected that people with the Negative Affect trait are more likely to have depression and that people with Type D personality are even more likely to report elevated depression scores, than people with only the Negative Affect trait. Method: The data from an online survey were used: the Diabetes MILES-Netherlands study. A number of 690 respondents, with the age 19 years or older and type 1 or type 2 diabetes, took part in this study. The respondents were divided into four groups: the Negative Affect only group (NA+/SI-), the Social Inhibition only group (NA-/SI+), the Type D group (NA+/SI+), and a control group named Low NA and SI group (NA-/SI-). The Inventory Depression Symptomatology (IDS) survey was used to measure the severity of depression. A multiple regression and an ANOVA were done to examine the association between Type D personality and comorbid-depression. Results: A correlation of r= 0,695, p<.01 was found between NA and depression. A correlation of r= 0,318, p<.01 was found between the trait SI and depression. Both correlations were found to be significant. 48,3% of the variance was explained by the traits NA (R 2 = 0,483) and 10,1% of the variance was explained by the trait SI (R 2 = 0,101). There was a significant effect of the traits of Type D personality on depression at the p<.05 level for the three conditions F(3, 681) = 119, p<.01. The group with high levels of Negative Affect 2

3 scored significantly higher on depression than the Low NA and SI -group and the Social Inhibited -group. Conclusion: People with Type D personality or high levels of Negative Affect could benefit from an adjusted treatment, where there is special attention for preventing or treating depression. 3

4 The potential role of Type D personality in people with diabetes with co-morbid depression. Diabetes is a complex metabolic disorder; untreated diabetes is characterised by chronic hyperglycaemia (American Diabetes Association, 2010). Diabetes can be categorized into two main categories, Type 1 diabetes and Type 2 diabetes (Aoife & Dinneen, 2014). Type 1 accounts for about 10% of the diabetes patients: in persons with type 1 diabetes, insulin-producing beta cells are destroyed or (almost) inactivated as a result of an autoimmune reaction. The exact cause of type 1 diabetes is still unknown. Type 1 diabetes can be diagnosed at any age, but is usually diagnosed before the age of 40. Type 2 diabetes is the most common form of diabetes, affecting approximately 90% of the diabetes patients. In type 2 diabetes, beta-cell dysfunction (beta-cells do not produce enough insulin) and insulin resistance (bodily cells have become less sensitive for insulin) cause elevated blood glucose levels, which require treatment with a diet, oral blood glucose lowering medication and/or insulin therapy. The majority of the cases with Type 2 diabetes develop in adulthood. However, nowadays Type 2 diabetes is becoming a health problem for adolescents and young adults as well, for example in the United States (Centre for Disease Control and Prevention, 2011). The most important risk factors for Type 2 are obesity, aging and physical inactivity (American Diabetes Association, 2010). After the diagnosis of diabetes, several lifestyle changes have to be made, which could reduce the quality of life (Narayan et al., 2000). For example, in persons with type 1 or type 2 diabetes who use insulin, blood glucose levels should be monitored, carbohydrates are often counted and food intake, insulin dosing and physical activity levels should be in balance to avoid hyper or hypoglycaemia. People with type 2 diabetes often have to make 4

5 dietary changes, quitting smoking if possible, increase physical activity levels and use of medications adequately (Narayan et al., 2000). In the long term, patients with diabetes have a higher risk of developing cardiovascular diseases (CVD). The DCCT study and the UKPDS study have shown that adequate glycemic control lowers the risk of developing micro-vascular complications affecting the eyes, kidneys and nerves (Canadian Diabetes Association, 2013). Additionally, poorly controlled diabetes increased the risk of hypertension and stroke, and can thus reduce life expectancy (Rubin & Peyrot, 1999). Beside the physical consequences, diabetes and its complications may also affect the mental health of an individual. Studies have shown that approximately 8-20% of the diabetes patients experience clinically relevant depressive symptoms. This continues to be twice as much as in the general population (Pouwer et al., 2003; Mezuk et al., 2008). Anxiety disorders affect on average 14% of the diabetes patients (Grisby et al., 2004). This is significantly higher than the general population, as only 0,9%-1,9% of the general population is diagnosed with an anxiety disorder (American Psychiatric Association, 2013). Systematic reviews show that patients who have diabetes combined with depression have a higher risk of developing diabetes-related complications than diabetic patients without depression. An increased risk of cardiovascular mortality is the largest physical risk for depressed diabetic patients (De Jonge et al., 2010). After taking the increased risk of micro vascular complications due to depression in account, depressed diabetic patients have a 1.5- fold increased risk of mortality than non-depressed diabetic patients (van Dooren et al., 2013). Patients with diabetes and co-morbid depression tend to show declined self-care behaviours, for example smoking, physical inactivity, alcohol consumption and unhealthy 5

6 eating habits (Gonzalez, 2008). This declined health-maintenance behaviour could be an explanation for the increased mortality rate in depressed persons with diabetes as well for the higher risk of CVD in diabetes (Verger, Lions & Ventelou, 2009). It is important to understand which pathways explain this increased mortality rate, allowing health care systems to customize their treatments and increase the diabetes outcomes for their patients. Several studies also found a bidirectional association between depression and type 2 diabetes (Renn, Feliciano & Segal, 2010). This suggests that diabetes could lead to depression, but depression may also lead to diabetes. Previous studies examined risk factors that could cause temporary stress, such as lower sense of mastery and functional limitations. However, few studies focused on the potential roll of personality traits, which are more permanent. One of the psychological factors that could influence physical health and the risk of depression, is Type D (Distressed) personality. It is characterized by the interaction of two traits: a high level of social inhibition and a high level of negative affectivity. People with Type D personality experience a lot of negative emotions, such as anxiety, sadness and anger. People with Type D personality typically tend not to share those emotions with others, out of fear of criticism or rejection from others (Denollet, 2005). As with (depressed) diabetic patients, individuals with Type D personality tend to show less self-care behaviour that increases the risk of health problems as well (Mommersteeg, Kopper & Denollet, 2010). Grande et al. (2012) found several studies investigating how Type D personality is related to CVD. Those longitudinal studies all found that having a Type D personality correlates with a higher risk for CVD. Type D personality is known to be a risk factor for physical, but also for psychological problems (e.g. depression and anxiety disorders) (Denollet, 2000; Mols & Denollet, 2010). Nefs et al. (2012) examined 6

7 the associations between Type D and self-care in people with diabetes and found that it is associated with declined self-care behaviour. In order to understand more about the potential role of Type D personality in people with diabetes and comorbid depression, this study will focus on the two different traits of Type D personality (negative affect and social inhibition). The main goal of this study is to plot the associations between negative affect (NA) and social inhibition (SI) and comorbid depression in people with diabetes. Since negative affect is one of the main aspects of a depression (Yamasaki, & Uchida, 2016), it is expected that people with the Negative Affect trait are more likely to report elevated depression scores, than people with only the Social Inhibition trait. Method Data collection The data for this study is derived from the Diabetes MILES-The Netherlands study (Browne, Nefs, Pouwer, and Speight, 2014). Diabetes MILES-The Netherlands conducted an online survey, which was open to people with any type of diabetes, aged 19 years (no upper age limit). The survey was widely advertised at a national level, resulting in a convenience sample. Diabetes MILES-The Netherlands received ethical approval from the Psychological Research Ethics Committee of Tilburg University (EC ). Participants A total of 3960 respondents took part in Diabetes MILES-The Netherlands. Participants who had a different type of diabetes than type 1 or type 2, were excluded from 7

8 the pooled dataset. After filtering for participants who filled in the DS14 (assessing type D personality) as well as the IDS-SR (depression), the dataset yielded 690 respondents for this study. The respondents were divided into four groups: participants with a high score on Negative Affect and a low score on Social Inhibition (NA+/SI-), named NA only, participants with a high score on Social Inhibition and a low score on Negative Affect (NA- /SI+), named SI only, participants with Type D personality; an high score on Negative Affect and Social Inhibition (NA+/SI+), named Type D and a control group; participants with a low score on Negative Affect and Social Inhibition (NA-/SI-), named Low NA and SI. Type D personality Type D personality was assessed using the Standard Assessment of Negative Affectivity, Social Inhibition and Type D Personality (DS14) (Denollet, 2005). The DS14 has adequate psychometric qualities, is stable over time and is independent of mood and health status (Browne et al., 2014). This survey consists two seven-item subscales of Negative Affectivity (NA) and Social Inhibition (SI). A Five-point rating scale ranging from 0 ( false ) to 4 ( true) is used to score the items. Type D is classified when a respondent obtains a score of ten or more on both scales. Depression The Inventory of Depressive Symptomatology (IDS-SR) (IDS-Guide, 2016) was used to measure depression. The IDS-SR is a self-inventory questionnaire, which contains 30 items with a 4 point rating scale. The total scores of the IDS-SR range from The 8

9 reliability of the IDS-SR is 0.94 Cronbach s Alpha. The psychometric qualities of the questionnaire are adequate (Rush et al., 1996). The results of the IDS-SR were classified into five groups, representing the severity of the depression. Group 0 (ranging from 0 till 13): no depression, group 1 (ranging from 14 till 25): mild depression, group 2 (ranging from 26 till 38): moderate depression, group 3 (ranging from 39 till 48): severe depression and group 4 (ranging from 49 till 84): very severe depression. Statistical methods The statistical analyses were preformed using SPSS Version 21 (IBM SPSS Statistics, New York). At first, information about the age, sex, type of diabetes, ethnicity, employment, and education were analysed using descriptive statistics. A multiple regression analysis was conducted, entering the two components of Type D personality (Negative Affect and Social Inhibition; both continuous, independent variables) and the depression score (continuous score, dependent variable). Differences in the severity of depression (continuous, dependent variable) between the four subgroups of traits were tested with a one-way ANOVA. The four subgroups were based on the different traits of Type D personality (categorical, independent variable). A p-value of 0,05 or lower was considered statistically significant. If the overall comparison from the ANOVA test was statistically significant, three planned comparisons were conducted ( Low NA and SI vs. Negative Affect only, Low NA and SI vs. Socially Inhibited only, Low NA and SI vs. Type D), using a Bonferroni adjusted level of 0.05/3 = Cohen s d was calculated as an index of effect size, with 0.20 (small), 0.50 (moderate) and 0.80 (large), respectively. 9

10 Results The demographics are represented in table 1 (E.g. the number of respondents, the group sizes, the average age, the number of males and females). Table 2 describes the outcomes of the IDS-SR stratified by the different traits of Type D personality. Table 3 shows the correlation between the traits of Type D and depression. Results Demographic characteristics Table 1 (appendix) summarises the demographic of the participants. In total 52% (n = 358) of the participants were male. The percentage of male participants varied per group from 39% - 60%. The average age of all the participants was 56 years, SD = 14, ranging per group from years. The average BMI-score of all the participants was 28 kg/m 2, SD = 6, ranging per group from 27-30, which means that on average the participants were moderate overweighed. A total of 688 (97%) participants had a Dutch nationality, ranging per group from 94%-97%. Overall, 330 (48%) of the participants were employed. This percentage differed per group, ranging from 46%-55%. The demographics also illustrated the type of education the participants had; 195 (28%) of all the participants had a low education, 230 (33%) of the participants had a medium high education and 263 (38%) of the participants were highly educated. A total of 292 (42%) participants had type 1 diabetes. The remaining group with type 2 diabetes contained 398 (58%) of the participants. Type D Personality Of a total of 690 participants, 202 (29%) were characterized as having a Type D personality. The group Negative Affect only contained 88 (13%) of the participants and the 10

11 group SI only contained 121 (18%) participants. The participants characterized as Low NA and SI accounted for 279 (40%) of the participants. This is shown in table 1 (see appendix). Depression On average, the participants scored M = 12, SD = 10 on the IDS. The Low NA and SI group scored M = 7, SD = 5 on the IDS, the NA only group had an IDS-score of M = 19 SD = 10, the SI only group had an IDS-score of M = 8, SD = 4 and the Type D group had an IDS-score of M = 19, SD = 11 (see table 2 in the appendix). The group with no depression based on the IDS contained 493 (64%) respondents. 184 (27%) respondents have a mild depression, 42 (6%) respondents have a moderate depression and 17 respondents (3%) have a severe depression. A multiple regression was conducted to report the associations between the two traits of Type D personality (NA and SI) and depression (see table 3 in the appendix). A correlation of r= 0,695, p<.01 was found between NA and depression. A correlation of r= 0,318, p<.01 was found between the trait SI and depression. Both correlations were found to be significant. 48,3% of the variance was explained by the traits NA (R 2 = 0,483) and 10,1% of the variance was explained by the trait SI (R 2 = 0,101). A one-way between subjects ANOVA was conducted to compare the role of Type D personality on depression, in Low NA and SI, NA only, SI only and Type D condition. There was a significant effect of the traits of Type D personality on depression at the p<.05 level for the three conditions F(3, 681) = 119, p<.01. A planned comparison (Bonferroni) reported that the NA only group scored significantly higher on depression compared to the Low NA and SI and SI only group (p<.01). The SI only group did not score significantly higher on depression compared to the Low NA and SI group (p=.828). 11

12 A Cohen s d was calculated as an index of effect size for the NA only group. The effect size of NA only group was Cohen s d=1.1, which means the effect of Negative Affect is respectively large. Discussion Type 2 diabetes is increasingly becoming a health problem (Centre for Disease Control and Prevention, 2011). One of the psychological factors that could influence physical health, is Type D (Distressed) personality. It is characterized by the interaction of two traits: a high level of social inhibition and a high level of negative affectivity (Denollet, 2005). Type D personality is known to be a risk factor for physical, but also for psychological problems (e.g. depression and anxiety disorders) (Denollet, 2000; Mols & Denollet, 2010). In order to understand more about the potential role of Type D personality in people with diabetes and comorbid depression, this study will focus on the two different traits of Type D personality (negative affect and social inhibition). The main goal of this study is to plot the associations between negative affect and social inhibition and comorbid depression in people with diabetes. Since negative affect is one of the main aspects of a depression (Yamasaki, & Uchida, 2016), it was expected that people with the Negative Affect trait are more likely to have depression. The results of this study support this hypothesis. A multiple regression reported a positive correlation between Negative Affect and depression. Which means that a higher score on the trait Negative Affect correlates strongly with a higher score on depression. 48,4% of the variance was explained by the traits NA and/or SI (R 2 = 0,484). There was also a positive correlation between SI and depression. This means that people with a higher score on 12

13 Social Inhibition tend to score higher on depression. 10,1% of the variance was explained by the trait SI (R 2 = 0,101). This is less than for the trait Negative Affect. Which was also reported in the calculated effect-sizes: A significant effect was found for the traits of Type D personality on depression. The NA only group scored significantly higher on depression than the SI only and Low NA and SI group. The SI only group did not score significantly higher on depression compared to the Low NA and SI group. The effect size of NA only group was Cohen s d=1.1, which means the effect of Negative Affect is large. The results of this study show that Negative Affect is associated with higher levels of depression. This was also seen in a previous study (Denollet et al., 2016), where Type D personality is also associated with higher levels of depression. Limitations Depression among the participants was measured by the scores on the IDS, which is a self-inventory questionnaire. This questionnaire only illustrates the depressive symptoms someone feels at the moment of has been feeling for the past few weeks. The IDS cannot be used to diagnose depression, since there will be missing valuable information that can only be retrieved from observations during an interviews. During a diagnostic psychiatric interview, questions can be explained or examples can be given. Diagnostic psychiatric interviews are therefore the gold standard for the diagnosis of depression. This is why a (additional) diagnostic psychiatric interview can be helpful in further research, to examine the associations between diagnosed depression and Type D personality in people with diabetes. The IDS-questionnaire is composed of depressive symptoms that respondents experience at the moment or has been feeling the past week. It could be that someone has been depressive in the past, but has overcome this depression by the time the questionnaire is 13

14 filled out. It could also be possible someone has no depressive feelings or symptoms at the moment, but will be depressive in the future. This is why a longitudinal study can be useful to illustrate this information in further research. The effects of having diabetes could also be overshadowing the effects of having Type D personality. Clinical implications Nowadays Type 2 diabetes is increasingly becoming a health problem for adolescents and young adults as well (Centre for Disease Control and Prevention, 2011). Diabetes can increase the changes of getting a depression (Pouwer et al., 2003; Mezuk et al., 2008). People with diabetes and comorbid depression are more likely to show declined self-care behaviour (Gonzalez, 2008). This could result into more negative effects of having diabetes. This is why mental health is important for diabetics. To prevent depression in people with diabetes, it could be useful to research the roll of the different traits of Type D personality. A significant effect was found for the traits of Type D personality on comorbid depression in people with diabetes 1 or diabetes 2. People with a high score on the trait Negative Affect tend to show significantly higher scores on depression. This implies that people with Type D personality as well as people with a high score on Negative Affect could benefit from an adjusted treatment, where there is special attention for preventing or treating depressions. Conclusion In conclusion, it appears that the traits of Type D personality may have a positive effect on developing comorbid depression in people with diabetes 1 or diabetes 2. Negative 14

15 affect is associated with significantly higher levels of depression. Social inhibition is also associated with higher levels of depression, but the effects are not significant. People with Type D personality or people with high levels of Negative Affect could benefit from an adjusted treatment, where there is special attention for preventing or treating depression. Future studies could control for the effects of having diabetes. It would also be helpful to do a longitudinal study and an interview to illustrate the depressive symptoms. 15

16 References American Diabetes Association (2010). Diagnosis and classification of diabetes mellitus. Diabetes Care, 33, American Psychiatric Association (2013). Diagnostic and statistical manual of mental disorders (5th ed.), Washington, DC: Author. Canadian Diabetes Association Clinical Practice Guidelines Expert Committee (2013). Definition, Classification and Diagnosis of Diabetes, Prediabetes and Metabolic Syndrome. Canadian Journal of Diabetes, 37, Clark, M.L., & Utz, S.W. (2014). Social determinants of type 2 diabetes and health in the United States. World Journal of Diabetes, 5, Cohen, J. (1992). A power primer. Psychological Bulletin, 112, Cond n, E., Ekselius, L., slund, C. (2013). Type D personality is associated with sleep problems in adolescents. Results from a population-based cohort study of Swedish adolescents. Journal of Psychosomatic Research, 74, De Jonge, P., Rosmalen, J.G., Kema, I.P., Doornbos, B., van Melle, J.P., et al. (2010) Psychophysiological biomarkers explaining the association between depression and prognosis in coronary artery patients: a critical review of the literature. Neuroscience and biobehavioral reviews, 39,

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18 Grigsby, A.B., Anderson, R.J., Freedland, K.E., et al. (2004). Prevalence of anxiety in adults with diabetes: a systematic review. Journal of Psychosomatic Research, 27, IBM Corporation. Released IBM SPSS Statistics for MacIntosh, Version Armonk, NY: IBM Corporation. IDS Guide ( ). Retrieved from Mezuk, B., Eaton, W.W., Albrecht, S., et al. (2008). Depression and type 2 diabetes over the lifespan: a meta-analysis. Diabetes Care, 31, Molenaar, E.A., Massaro, J.M., Jacques, P.F., Pou, K.M., Ellison, R.C., et al. (2009): Association of lifestyle factors with abdominal subcutaneous and visceral adiposity: the Framingham Heart Study. Diabetes Care, 32, Mols, F., Denollet,J. (2010). Type D personality among non-cardio vascular patient populations: a systematic review. General Hospital Psychiatry, 32, Mommersteeg, P.M.C., Kupper, N., & Denollet, J. (2010). Type D personality is associated with increased metabolic syndrome prevalence and an unhealthy lifestyle in a cross sectional Dutch community sample. MC Public Health, 10,

19 Pouwer, F., Beekman, A.T.F., Nijpels, G., Dekker, J. M., Snoek, F. J., et al. (2003). Rates and risks for co-morbid depression in patients with Type 2 diabetes mellitus: results from a community-based study. Diabetologia, 46, Pouwer, F. (2013). Depression and Risk of Mortality in People with Diabetes Mellitus: A Systematic Review and Meta-Analysis. PLoS ONE, 8, e Psychosomatics, 49, Renn, B.N., Feliciano, L., & Segal, D.L. (2011). The bidirectional relationship of depression and diabetes: A systematic review. Clinical Psychology Review, 31, Rubin, R., & Peyrot, M. (1999). Quality of life and diabetes. Diabetes/Metabolism Research and Reviews, 15, Rush, A.J., Carmody, T. and Reimitz, P.E. (2000). The Inventory of Depressive Symptomatology (IDS): Clinician (IDS-C) and self-report (IDS-SR) ratings of depressive symptoms. International Journal of Methods in Psychiatric Research, 9, Van Dooren, F.E.D., Nefs, G., Schram, M.T., Verhey, F.R.J., Denollet, J., & Venkat Narayan, K.M., Gregg, E.W., Fagot-Campagna, A., Engelgau, M.M., & Vinicor, F. (2000). Diabetes a Common, Growing, Serious, Costly, and Potentially Preventable Public Health Problem. Diabetes Research and Clinical Practice, 50,

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21 Appendix Table 1. Demographic characteristics stratified by the four NA/SI-groups All Low NA and SI NA only SI only Type D N 690 (100%) 279 (40%) 88 (13%) 121 (18%) 202 (29%) Male 358 (52%) 143 (51%) 38 (43%) 73 (60%) 78 (39%) Age, years 56 ± ± ± ± ± 15 Type of Diabetes Type (42%) 121 (43%) 35 (40%) 52 (43%) 84 (42%) Type (58%) 158 (57%) 53 (60%) 69 (57%) 118 (58%) BMI 28 ± 6 27 ± 5 29 ± 6 27 ± 5 30 ± 7 Dutch Nationality 688 (97%) 271 (97%) 85 (97%) 115 (95%) 190 (94%) Employed 330 (48%) 152 (55%) 46 (52%) 56 (46%) 104 (52%) Education low 195 (28%) 69 (25%) 30 (34%) 30 (25%) 66 (33%) middle 230 (33%) 98 (35%) 30 (34%) 33 (27%) 69 (34%) high 263 (38%) 110 (39%) 28 (32%) 58 (48%) 67 (33%) Values are n(%) or mean ± SD Table 2. Clinical outcomes stratified by the four NA/SI-groups All Low NA and SI NA only SI only Type D N 690 (100%) 279 (40%) 88 (13%) 121 (18%) 202 (29%) Depression score 12 ± 10 7 ± 5 19 ± 10 8 ± 4 19 ± 11 Depression severity none 439 (64%) 242 (87%) 29 (33%) 95 (79%) 73 (36%) Values are n(%) or mean ± SD mild 184 (27%) 43 (12%) 44 (50%) 24 (20%) 82 (41%) moderate 42 (6%) 1 (0%) 10 (11%) 1 (1%) 30 (15%) severe 17 (3%) - 4 (5%) - 13 (6%) very severe 3 (0%) - 1 (0%) - 2 (1%) 21

22 Table 3. The correlation between depression and the two traits of Type D personality Depression NA SI Mean ± SD Depression.,695**.,318** 12,4 ± 9,6 NA.,695**.,486** 8,8 ± 6,3 SI.,318**.,468** 9,4 ± 6,4 *p <.05, **p <.01 22