Objective: Night eating syndrome is characterized by evening overeating (hyperphagia) and/or nocturnal awakenings with ingestion of food conceptualized as a delay in the circadian pattern of food intake. In this syndrome morning anorexia, insomnia, depressed mood that worsens in the evening are also observed. Although the etiology of NES is unknown; it’s thought that genetic factors may involve. However, a small number of study is conducted about this subject. A first step in understanding potential genetic and environmental inşuences is a study of familial aggregation. It is aimed to show the existence and importance of genetic inheritance factors involved in the etiology of the NES reported by a case of familial aggregation of NES.
Method: Three individuals from same family who referred to a psychiatry clinic are diagnosed with NES by psychiatrists with clinical examination and scales. As remarkable findings on this case are discovered, first degree relatives of this family are invited for an interview. The family tree (pedigree) below is generated by psychiatric diagnose records of participant family members and the information obtained from them about the other family members. The doubtful information obtained from family members are ignored, definite diagnosis by a psychiatrist is recorded with the confirmation of participant family members.
Pedigree: Family members with or without NES or with other psychiatric disorders are shown below according to this method.
Discussion: A family study conducted by Lundgren et al. found the risk of NES is five times greater in relatives of individuals with NES than in unaffected individuals. Similar findings of Lamerz et al. study showed that risk for NES among children of mothers with NES is 7.8 times greater than among children of mothers without NES. Also a twin study reported moderate heritability for both males and females. Our family case report provides suggestive evidence that a familial hereditary transmission may play a role in the development of NES. Like other eating disorders, NES is comorbid with psychiatric disorders. It’s remarkable that we found high co-existence of mood disorders such as depression, dysthymia, bipolar disorder with NES in the family case that we reported. The association of bipolar disorder with other eating disorders as bulimia nervosa, binge eating and also with NES is not clearly known. More studies on this subject will contribute to a better understanding etiology of NES. This study was limited for certain inferences in the following ways, first the diagnoses are made from the family history method, rather than the family interview method, second the familial hereditary transmission is also observed in other psychiatric disorders.
Results: This case report provided that NES is an entity that should be cautiously consider in psychiatry practice when the heritability, frequency, the association with other psychiatric disorders are kept in mind. It is obvious that genotype studies concerning the chronobiology that can be involve disorders such as sleep, eating and mood disorders will contribute to better understanding of etiology of NES and other psychiatric disorders.