The majority of patients with DID report childhood sexual or physical abuse, though the accuracy of these reports is controversial. Amnesia between identities may be asymmetrical; identities may or may not be aware of what is known by another. Individuals with DID may be reluctant to discuss symptoms due to associations with abuse, shame, and fear. DID patients may also frequently and intensely experience time disturbances.Around half of people with DID have fewer than 10 identities and most have fewer than 100; although as many as 4,500 have been reported. (p 503) The average number of identities has increased over the past few decades, from two or three to now an average of approximately 16. However, it is unclear whether this is due to an actual increase in identities, or simply that the psychiatric community has become more accepting of a high number of compartmentalized memory components. Comorbid disorders
The psychiatric history frequently contains multiple previous diagnoses of various disorders and treatment failures. The most common presenting complaint of DID is depression, with headaches being a common neurological symptom. Comorbid disorders can include substance use disorder, eating disorders, anxiety disorders, bipolar disorder, and personality disorders. A significant percentage of those diagnosed with DID have histories of borderline personality disorder and post-traumatic stress disorder (PTSD). Presentations of dissociation in people with schizophrenia differ from those with DID as not being rooted in trauma, and this distinction can be effectively tested, although both conditions share a high rate of dissociative auditory hallucinations.
Other
Effects of EGFEpidermal growth factor (EGF) results in cellular proliferation, differentiation, and survival. EGF is a low-molecular-weight polypeptide first purified from the mouse submandibular gland, but since then found in many human tissues including the submandibular gland, and the parotid gland. Salivary EGF, which also seems to be regulated by dietary inorganic iodine, also plays an important physiological role in the maintenance of oro-oesophageal and gastric tissue integrity. The biological effects of salivary EGF include healing of oral and gastroesophageal ulcers, inhibition of gastric acid secretion, stimulation of DNA synthesis, and mucosal protection from intraluminal injurious factors such as gastric acid, bile acids, pepsin, and trypsin and from physical, chemical, and bacterial agents. Stomach as nutrition sensorThe human stomach can "taste" sodium glutamate using glutamate receptors and this information is passed to the lateral hypothalamus and limbic system in the brain as a palatability signal through the vagus nerve. The stomach can also sense, independently of tongue and oral taste receptors, glucose, carbohydrates,  proteins, and fats. This allows the brain to link nutritional value of foods to their tastes. Thyrogastric syndromeThis syndrome defines the association between thyroid disease and chronic gastritis, which was first described in the 1960s. This term was coined also to indicate the presence of thyroid autoantibodies or autoimmune thyroid disease in patients with pernicious anemia, a late clinical stage of atrophic gastritis.