Development of NES Screening Tool 1 Selection of Items

The 2003 NES criteria require other ED to be absent before a diagnosis of NES can be made. WMC clinic resources did not allow for an in-depth assessment of every individual by an eating disorder specialist. Validated tools already existed which could be used to eliminate other eating disorders. In order to develop one, easily administered, composite NES screening tool which would be suitable for an obese UK population, core elements of tools used to identify other ED were combined with items from Stunkard‟s NEQ (2004). As there were no known subjects with NES with whom key constructs could be debated, it was necessary to focus on the four main behavioural constructs contained in Stunkard‟s 2003 diagnostic criteria. The four constructs are morning anorexia, evening hyperphagia, nocturnal awakenings and overnight snacking.

Questionnaire items based on these constructs, along with other items, had originally been included in the 2003 NESQ (Wadden & Phelan 2002) which was adopted into the NEQ. For the purposes of this study, items from the NEQ were either chosen by JC for inclusion in the study screening tool, or rejected, depending on whether they reflected the four main constructs. Included items are listed below.

Morning anorexia

 How hungry are you usually in the morning?  When do you usually eat for the first time?

Evening hyperphagia

60  Do you have urges to eat snacks after suppertime but before bedtime?

Nocturnal awakenings

 How often do you have trouble getting to sleep?

 Apart from getting up to go to the toilet, how often do you get up at least once in the middle of the night?

Overnight snacking

 When you get up in the middle of the night, how often do you snack?  If you snack in the middle of the night, how aware are you of your eating?

Low mood

Two questions relating to mood were also included. Although low mood is not listed as a core criterion for NES, these items were included as studies have consistently noted the distinctive circadian features of the mood patterns of NES sufferers and Stunkard includes mood items in the NESQ and NEQ (Birketvedt et al. 1999;Birketvedt, Sundsfjord, & Florholmen 2002;Gluck, Geliebter, & Satov 2001;Marshall et al. 2004). Stunkard uses American terminology to ask whether subjects ever feel „blue‟ and the items were adapted to reflect more familiar English terminology.

 Do you ever feel low in mood?

 When you are feeling low in mood, is your mood better in the early morning / late morning / afternoon / early evening/ late evening?

Breakfast

The question „Do you find it difficult to eat breakfast?‟ had originally been included in the WALI but removed by Stunkard, on the grounds that it was similar to the question „how hungry are you usually in the morning?‟ After discussion with 3 local clinic dietitians, it was decided to reintroduce this item, in order to characterise better the construct of morning anorexia as most subjects in obesity clinics report not feeling hungry in the morning, even if they are compliant with eating breakfast.

61 3.4.3.2. Excluded Items

Two items, „Do you need to eat in order to get back to sleep when you awake at night?‟ and „Do you have cravings or urges to eat snacks when you wake up at night?‟ were excluded on the grounds that they were potentially open to misinterpretation. Positive responses would not necessarily signify that an individual had actually eaten anything. Two further items relating to control over night snacking, „How much control do you have over your eating while you are up at night?‟ and „how much control do you have over your eating between supper and bed time?‟ were also excluded as the issue of control is not included in the diagnostic criteria.

3.4.3.3. Items Included Based on Other Diagnostic Criteria

Extra items were also included in the tool which reflected the two other components of the diagnostic criteria, namely duration of the behaviours and absence of other eating disorders. „How long have you experienced your current pattern of eating and sleeping?‟ had been asked by Stunkard as a stand-alone question at the end of the NEQ. In order to standardise the format of the study screening tool, it was included here as a Likert scale question, with scores ranging from 0-4 depending on whether the duration was zero, less than 3 months, less than 6 months less than 12 months or above 12 months. Behaviour of longer duration was given a higher score as a chronic problem is more likely to have a greater impact on the individual.

With regard to the exclusion of other eating disorders, identifying suitable items for inclusion in the screening tool was problematic as other validated tools such as the EAT (Eating Attitudes Test) or BITE (Bulimic Investigatory Test) tend to be lengthy, including 40 and 30 items respectively and would be impractical for adding to another tool (Garner & Garfinkel 1979;Henderson & Freeman 1987). By contrast, the SCOFF questionnaire is a short, 5-item, validated and reliable diagnostic tool with good sensitivity and specificity for diagnosing BU and AN, which has been previously administered both verbally and in writing (Morgan, Reid, & Lacey 1999). Four of the SCOFF items listed below were included in the screening tool:

 Have you recently lost more than 1 stone in a 3 month period? (please circle yes or no)

 Would you say that food dominates your life?

 Do you worry you have lost control over how much you eat?

62 The fifth SCOFF item, „Do you believe yourself to be fat when others say you are thin?‟ was not included as it was considered to be inappropriate for morbidly obese subjects. A positive response to two or more of the SCOFF items indicates a likely case of either AN or BU. With regard to BED, one question was included in the screening tool which is based on Spitzer‟s validated core criteria for BED (Spitzer et al. 1993).

 Do you ever eat large amounts of food in a short period of time (larger than most people would eat during a similar time and under similar circumstances)?

Also, one of the SCOFF items, „Do you worry you have lost control over how much you eat?‟ concerns loss of control over eating which reflects the second key construct of BED (Spitzer et al. 1993). In total, the final version consisted of a 17 item Likert scale screening tool (Appendix 4), the contents of which were discussed with the 3 obesity clinic dietitians in order to establish face validity. Each item had a potential score ranging from 0-4 and item scores, when combined, produced a total score ranging from 0-68. It was envisaged that testing of the tool in the WMC would produce cut points that supported its use as a screening tool for NES in an obese clinic population.