Core Criterion B

‘Awareness and recall of evening and nocturnal episodes are present’

This criterion was not included in the 2003 criteria and is usually not reported in papers, although it is assumed in the literature that NES individuals have full awareness of their

behaviour, otherwise they would be classed as Sleep Related Eating Disorder (Devlin 2007;Howell, Schenck, & Crow 2008). This suggests a dichotomous classification where

awareness is completely present or absent. This experience was not reflected in the identification or characterisation studies, where the degree of awareness varied considerably both between and within individual reports, although distress and behaviour associated with other parasomnia such as sleep walking were not reported. Some individuals gave conflicting reports at various stages in the interview while others supported Allison‟s findings that individuals often report lack of awareness initially, but can recall events with further probing (Allison et al. 2010b). Whilst an individual‟s reluctance to admit to an apparently shameful and secretive behaviour may have an effect on initial reporting, measures for defining and reporting awareness in order to distinguish NES from other sleep disorders need to be more robust. It might be helpful to include items in the NESHI which help obesity and ED specialists to distinguish NES from other sleep disorders. 6.2.4.3. C Core Descriptors

‘The clinical picture is characterised by at least three of the following features: The 2010 criteria propose that 3 of the following 5 descriptors are required for a diagnosis of NES, although all but one appear common in obese populations regardless of NES diagnosis.

1. ‘Lack of desire to eat in the morning and/or breakfast is omitted on 4or more mornings per week’.

Striegel Moore‟s typology study (Striegel-Moore et al. 2008) noted a strong negative linear relationship between night-eating and morning anorexia and this criterion has been a consistent

174 feature of all versions of NES criteria. However, this relationship is also true of morning

anorexia and chronic obesity (Huang et al. 2010) and its relevance as a distinguishing feature of NES in a morbidly obese population remains doubtful. No difference was noted between the NEB group and the non-NEB group on the morning anorexia item of the NEQ (2004). Seventy three percent of the identification study sample reported not eating breakfast and the true rate was probably higher, as several of those eating breakfast were probably doing so reluctantly in order to comply with dietetic advice. Whilst this descriptor is likely to be helpful as a

distinguishing feature in normal weight individuals it is of little use in a morbidly obese population.

2. ‘Presence of a strong urge to eat between dinner and sleep onset and/or during the night’.

In the identification study, a significant difference was noted between the NEB and non-NEB group for the items relating to eating after the evening meal and the urge to eat at night. Given the substantial variability in evening and night-eating in this obese population it is possible that the cognitions and behaviours driving the urge to eat are more relevant than the timings of meals/snacks and amounts eaten. Individuals with NEB reported greater loss of control during these eating episodes in particular and during eating episodes generally. As previously

discussed, perceived loss of control is a classic feature of many ED sufferers who report having less personal control over outcomes in the world and a tendency to attribute the cause of „bad‟ life events to aspects of themselves. Future areas of research need to examine whether NEB individuals share this distinctive emotional make-up and are characterized by an external locus of control and poor self efficacy, making them less able to control their eating patterns and whether this is a distinctive feature of NEB as opposed to morbid obesity.

3. „Presence of a belief that one must eat in order to initiate or return to sleep’

Evidence from the characterisation study showed that obese individuals often wake up at night and get out of bed for a variety of reasons, mainly to go to the toilet. Getting up for a drink is very common and yet only some individuals will go on to eat before returning to bed, describing a strong compulsion to do so. Clearly, obese individuals are often presented with opportunities to eat at night and yet only some individuals will feel this compulsion. In an obese population,

175 this appears to be the one key distinguishing feature that separates night-eaters from non-night- eaters and adds weight to the argument that obese NEB sufferers either have different cognitions and emotions to obese individuals without NEB, or that they all have similar cognitions, but some individuals find restraint at high risk times easier than others. The psychological profile of poor sleepers having anxiety–prone, obsessive-worrisome personalities did not seem particularly applicable to this NEB group, who reported less emotional reasons for waking up, compared to the non-NEB group. A greater understanding of the NEB „personality type‟, above and beyond the obese „personality type‟ may help to answer these questions.

4. Sleep onset and or/sleep maintenance insomnia are present four or more nights per