Ith several large population studies reporting a dose esponse relationship between

Ith several large population studies reporting a dose esponse relationship between short sleep duration and excess body weight in infants, adolescents and adults of varying ethnicities.90 Other studies have shown a link between obesity, short sleep duration and poor sleep quality with improvements in sleep quality noted in obese individuals after a 5 weight loss.91?3 The relationship between rising BMI and the risk of developing obesity-related comorbidity such as Obstructive Sleep Apnoea (OSA), type 2 diabetes and the metabolic syndrome is also known.94 These conditions are also associated with poor sleep quality and excessive day-time sleepiness.95,96 Short and long sleep durations increase the risk of developing type 2 diabetes independent of known confounding factors and poor sleep quality is associated with worsening glycaemic control in diabetes.97 Increasing BMI is also associated with the debilitating effects of chronic pain, which is in turn associated with depression and anxiety.98 Several studies have also demonstrated a link between poor subjective sleep quality and depression.99 The neurobiology of disturbed sleep in depression includes disturbances in the electrophysiological architecture and functional deviations in different brain regions, resulting in a decrease in slow wave sleep and increased awakenings.100 Various hypothesis also suggest a relationship between obesity and depression. Rosmond considers both to be manifestations of the brain serotonin deficiency and obesity to be the clinical manifestation of a subtype of depression similar to that of atypical depression.101 However, the majority of evidence suggests they are separate constructs, having an influencing effect on each other. Obesity can develop subsequent to depression as a result of reduced activity and comfort eating, or obesity-related impairments, such as fatigue and weight-related stigma may result in depression.102,103 Improvements in depressed mood are noted after weight loss due to changes in physical appearance and improvements in LY2510924 chemical information eating patterns.104 Implications for NES Short sleep duration is associated with lower leptin and higher ghrelin levels in fasting morning blood, hormone changes which are typically associated with increased appetite and also seen in NES individuals.105,106 It is possible that sleep duration may have a part in the pathogenesis of NES, through its association with obesity,105,107 although current evidence linking NES and short sleep duration is mixed. O’Reardon et al.24 found no difference in sleep duration between NES and non-NES individuals (mean BMI 34.9 kg m ?2 and 36.7 kg m ?2, respectively), yet Rogers et al.3 noted significantly shorter sleep duration in NES females with similar BMI levels. The relationship between sleep duration and severe obesity is not known. Serotonin promotes satiety and is replaced during sleep. Disturbed sleep may reduce natural levels2012 Macmillan Publishers Limitedand increase the need for exogenous sources such as carbohydrates, resulting in obesity. Night snacks consumed in NES are typically carbohydrate rich (73 ), with a high carbohydrate to protein ratio (7:1).23 Individuals with NES report more difficulty in getting to sleep, but whether this is due to a psychological BX795 web factor or the physical effect of comorbidity is unclear as sleep patterns are currently not reported consistently in NES studies or measured routinely in obese populations. NES is common in individuals with schizoph.Ith several large population studies reporting a dose esponse relationship between short sleep duration and excess body weight in infants, adolescents and adults of varying ethnicities.90 Other studies have shown a link between obesity, short sleep duration and poor sleep quality with improvements in sleep quality noted in obese individuals after a 5 weight loss.91?3 The relationship between rising BMI and the risk of developing obesity-related comorbidity such as Obstructive Sleep Apnoea (OSA), type 2 diabetes and the metabolic syndrome is also known.94 These conditions are also associated with poor sleep quality and excessive day-time sleepiness.95,96 Short and long sleep durations increase the risk of developing type 2 diabetes independent of known confounding factors and poor sleep quality is associated with worsening glycaemic control in diabetes.97 Increasing BMI is also associated with the debilitating effects of chronic pain, which is in turn associated with depression and anxiety.98 Several studies have also demonstrated a link between poor subjective sleep quality and depression.99 The neurobiology of disturbed sleep in depression includes disturbances in the electrophysiological architecture and functional deviations in different brain regions, resulting in a decrease in slow wave sleep and increased awakenings.100 Various hypothesis also suggest a relationship between obesity and depression. Rosmond considers both to be manifestations of the brain serotonin deficiency and obesity to be the clinical manifestation of a subtype of depression similar to that of atypical depression.101 However, the majority of evidence suggests they are separate constructs, having an influencing effect on each other. Obesity can develop subsequent to depression as a result of reduced activity and comfort eating, or obesity-related impairments, such as fatigue and weight-related stigma may result in depression.102,103 Improvements in depressed mood are noted after weight loss due to changes in physical appearance and improvements in eating patterns.104 Implications for NES Short sleep duration is associated with lower leptin and higher ghrelin levels in fasting morning blood, hormone changes which are typically associated with increased appetite and also seen in NES individuals.105,106 It is possible that sleep duration may have a part in the pathogenesis of NES, through its association with obesity,105,107 although current evidence linking NES and short sleep duration is mixed. O’Reardon et al.24 found no difference in sleep duration between NES and non-NES individuals (mean BMI 34.9 kg m ?2 and 36.7 kg m ?2, respectively), yet Rogers et al.3 noted significantly shorter sleep duration in NES females with similar BMI levels. The relationship between sleep duration and severe obesity is not known. Serotonin promotes satiety and is replaced during sleep. Disturbed sleep may reduce natural levels2012 Macmillan Publishers Limitedand increase the need for exogenous sources such as carbohydrates, resulting in obesity. Night snacks consumed in NES are typically carbohydrate rich (73 ), with a high carbohydrate to protein ratio (7:1).23 Individuals with NES report more difficulty in getting to sleep, but whether this is due to a psychological factor or the physical effect of comorbidity is unclear as sleep patterns are currently not reported consistently in NES studies or measured routinely in obese populations. NES is common in individuals with schizoph.