The present study had few main goals, which required different research designs. First of all, the study aimed to test whether different groups of participants (i.e., BED-O and Non-BED-
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O; IV) display differing levels of (1) trait EI and its compounding constructs and dimensions (DVs); (2) overeating behaviours (DVs); and (3) coping styles (DVs). For this research goal, the employed design was a between-subjects one, and the statistical analyses conducted consisted of independent samples t-tests. The second goal of the research was to investigate whether EI trait and its constituting constructs and dimensions (IVs) predict the engagement in overeating behaviours (DVs). This can be categorized as a correlational research design, whereby the analyses conducted consisted of hierarchical regression models. Finally, the study aimed to test whether coping styles (MVs) mediate the association between trait EI (IV) and overeating behaviours (DVs), while controlling for depression scores (MV). This can also be classified as correlational research design, with the statistical analyses consisting of regression analyses and Sobel test. As noted by Field (2009), Sobel test requires all variables to have a normal distribution, especially in cases when the sample size is larger than 100. Normal distribution was checked for the following variables: coping styles, trait EI, overeating behaviours, and depression. Figure 2 in Appendix A presents histograms showing the distribution of these variables. Almost all variables had a normal distribution (as revealed by the bell-shaped curve). Only depression scores revealed a slightly skewed data – however, this was not deemed as an issue because depression scores were mainly a control variable.
5.4. Measures
Participants were asked to complete a series of measures, assessing their (1) demographic characteristics, (2) binge eating symptomatology, (3) trait emotional intelligence, (4) overeating behavioural patterns (i.e., emotional, external, and restrained eating), (5) coping styles, and (6) depression. The full questionnaire can be seen in Appendix F.
Demographics. In assessing demographic characteristic of the sample, participants were
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and height data, participants’ BMI was calculated. This was achieved by dividing participants’ weight in kilograms by their height in meters squared (i.e., [weight in kg] / [height x height in m]).
Binge eating symptomatology. To assess binge eating symptomatology, the employed
measure was Questionnaire on Eating and Weight Patterns - Revised (QEWP-R; Yankovski, 1993). This questionnaire provides decision rules for the differential diagnosis of the presence or absence of BED, which is completed by asking participants to indicate whether they have eaten unusually large quantities of food within a two-hour period during the last 6 months, and whether they have, during the times when they ate an unusually large quantities of food, felt that they could not stop eating or control how much they were eating. Following the DSM-IV criteria, participants who answered these questions with “no” were categorized as belonging to the Non-BED-O group, and participants who provided “yes” answers were categorized as belonging to the BED-O group. Moreover, participants who answered with “yes” were asked to complete another set of questions that more thoroughly investigated the severity of binge eating symptomatology. These questions focused on the (1) frequencies of binge episodes, (2) the presence of binge eating symptoms (e.g., eating until being uncomfortably full, feeling embarrassed by the quantities of food eaten, etc.), (3) time of the day when binge episodes start, (4) the duration of the binge episodes, (5) type of food eaten during the episodes, and (6) the degree of the engagement in compensatory behaviours. Importantly, the QEWP-R questionnaire has been proved to be both reliable (Cronbach alpha = .79) and valid (r = .83) when it comes to differentiating between the presence or absence of BED and assessing BED-related symptomatology (Yankovski, 1993; Nangle et al., 1993).
Emotional intelligence trait. The extent to which participants possess the EI trait was
assessed by relying on the Trait Emotional Intelligence Questionnaire (TEIQue; Petrides, 2009). This measure consists of 153 statements, where participants are asked to indicate the
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degree to which they agree with them, on a scale ranging from 1 (completely disagree) to 7 (completely agree). The items are measuring 4 compounding constructs and dimensions that underlie those constructs. These include the constructs of well-being (dimensions: optimism, happiness, and self-esteem), self-control (dimensions: emotional regulation, stress management, and impulsiveness), emotionality (dimensions: emotional perception, emotional expression, social relationships, and empathy), and sociality (dimensions: emotional management, assertiveness, and social awareness). The example question for the well-being subscale includes “I generally hope for the best”; for the self-control subscale “I tend to rush
into things without too much planning”; for the emotionality subscale “Many times, I cannot figure out what emotion I am feeling”; and the example question for the sociality subscale
includes “If I wanted to, it would be easy for me to make someone feel bad”. Before calculating means on each subscale, some items needed to be reverse-scored, so that higher scores indicate higher possession of the trait EI, its compounding constructs, and their dimensions. The final mean score on the whole scale, on each compounding construct of the scale, and on each dimension that makes up a compounding construct ranged from 1 to 7. Importantly, the scale has a well-demonstrated internal reliability (Cronbach alpha = .82) and convergent validity (r = .74) (Petrides & Furnham, 2003). In this research, the Cronbach alpha for the whole scale was .79, thus indicating good internal reliability.
Eating behaviours. Eating behaviours were assessed by the Dutch Eating Behaviour
Questionnaire (DEBQ; Van Streien et al., 1986). Here, participants are presented with 33 questions relating to the engagement in a particular eating behaviour, for which they are supposed to indicate how often they engage in them, on a scale ranging from 1 (never) to 5 (very often). These questions are assessing three types of eating patterns, with these being emotional eating (e.g., “Do you have the desire to eat when emotionally upset?”), external eating (e.g., “If food smells and looks good, do you eat more than usual?”), and restrained
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eating (e.g., “How often do you refuse food or drink because you are concerned about your
weight?). None of the items needed to be reverse-scored. The final score on the emotional
eating subscale ranged from 13 to 65, and on the external eating and restrained eating subscales from 10 to 50, with higher scores indicating more engagement in a particular eating behaviour. The scale’s internal reliability (Cronbach alpha = .96) and convergent validity (r = .86) have been well-established (Wardle, 1987). In the present research, the Cronbach alpha for this scale was .95, thus indicating excellent internal reliability.
Coping styles. This construct was assessed by using the Coping Styles Questionnaire (CSQ;
Roger et al., 1993). The questionnaire contains 48 statements, for which participants are asked to indicate how often those statements correspond to the ways they typically react to stress, on a scale ranging from 0 (always) to 3 (never). The scale assesses four underlying coping styles, including emotional coping style (e.g., “I become miserable and depressed”), rational coping style (e.g., “I try to find out more information to help make a decision about
things”), avoidance coping style (e.g., “I sit tight and hope it all goes away”), and detached
coping style (e.g., “I see the problem as something separate from myself so I can deal with
it”). All items needed to be reverse-scored so that higher scores on each subscale represent
higher reliance on a particular coping style. The final score on each subscale ranged from 0 to 58. Importantly, the choice was also to calculate the final scores for adaptive and maladaptive coping. The score for adaptive coping was calculated by taking means of rational and detached coping styles scores, whereas the score for maladaptive coping was computed by taking means of emotional and avoidance coping styles scores. As it was the case with all previous mentioned measures, this one also has an established internal reliability (Cronbach alpha = .84) and convergent validity (r = .78) (Elklit, 1996). In the present sample, the Cronbach alpha for this scale was .71, thus revealing acceptable internal reliability.
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Depression. To measure participants’ levels of depression, the employed measure was the
Patient Health Questionnaire (PHQ-9; Kroenke & Spitzer, 2002). This rather brief scale instructs participants to indicate how often, over the last two weeks, have been bothered by particular problems. The scale further presents participants with 9 problems that relate to depression-related symptomatology (e.g., “Feeling bad about yourself – or that you are a
failure or have let yourself or your family down”; “Trouble falling or staying asleep, or sleeping too much”), and which need to be scored on a scale ranging from 1 (not at all) to 4
(nearly every day). Following these 9 items, the scale presents participant with an additional one, assessing the degree of difficulty these problems have made, therefore assessing the severity of depression (i.e., “If you checked off any problems, how difficult have these
problems made it for you to do your work, take care of things at home, or get along with other people?”). This item is assessed on a scale ranging from 1 (not difficult at all) to 4
(extremely difficult). The final score on the scale ranges from 10 to 40, with higher scores indicating higher levels of depression. The scale has a well-established internal reliability (Cronbach alpha = .91) and convergent validity (r = .87) (Martin, Rief, Klaiberg, & Braehler, 2006). In the present sample, the Cronbach alpha for this scale was .90, thus indicating excellent internal reliability.
5.5. Procedure
The research began with the recruitment procedure, which was conducted by providing all patients in a diabetic clinic in Wales with a self-addressed envelope that contained the information regarding the research, together with the questionnaires that needed to be completed. Participants were also provided with an informed consent where they were informed that they can withdraw from the study at any moment (See participant information sheet in appendix 1 under RES 20B – appendices C). However, no participant expressed a desire to actually withdraw from the research. Within the questionnaires itself, participants
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first completed the measure of BED symptomatology, followed by the measure of trait EI, overeating behaviours, coping styles, and depression. Recruitment procedure was supervised by a practicing nurse in the clinic, who collected the completed questionnaires and forwarded them to the researcher. The researcher then entered all data in SPSS.