Bulimia also has negative effects on a persons teeth due to the acid passed through the mouth from frequent vomiting causing acid erosion, mainly on the posterior dental surface. Research has shown that there is a relationship between bulimia and narcissism. According to a study by the Australian National University, eating disorders are more susceptible among vulnerable narcissists. This can be caused by a childhood in which inner feelings and thoughts were minimized by parents, leading to "a high focus on receiving validation from others to maintain a positive sense of self".The medical journal Borderline Personality Disorder and Emotion Dysregulation notes that a "substantial rate of patients with bulimia nervosa" also have Borderline personality disorder.A study by the Psychopharmacology Research Program of the University of Cincinnati College of Medicine "leaves little doubt that bipolar and eating disorders—particularly bulimia nervosa and bipolar II disorder—are related." The research shows that most clinical studies indicate that patients with bipolar disorder have higher rates of eating disorders, and vice versa. There is overlap in phenomenology, course, comorbidity, family history, and pharmacologic treatment response of these disorders. This is especially true of "eating dysregulation, mood dysregulation, impulsivity and compulsivity, craving for activity and/or exercise. "Studies have shown a relationship between bulimias effect on metabolic rate and caloric intake with thyroid dysfunction. Causes
Biological
As with anorexia nervosa, there is evidence of genetic predispositions contributing to the onset of this eating disorder. Abnormal levels of many hormones, notably serotonin, have been shown to be responsible for some disordered eating behaviors.
Cold turkey is the most effective treatment method, as it directly removes the cause of the condition, yet the time period between the discontinuation of the drug and the relief of symptoms may be too long and uncomfortable for some individuals (particularly when trying to go to sleep when they are unable to breathe through their nose). The use of over-the-counter (OTC) saline nasal sprays may help open the nose without causing RM if the spray does not contain a decongestant. Symptoms of congestion and runny nose can often be treated with corticosteroid nasal sprays under the supervision of a physician. For very severe cases, oral steroids or nasal surgery may be necessary. For RM caused by topical decongestants, there are anecdotal reports of persons having success by withdrawing treatment from one nostril at a time.A study has shown that the anti-infective agent benzalkonium chloride, which is frequently added to topical nasal sprays as a preservative, aggravates the condition by further increasing the rebound swelling. See also
Topical decongestant

References
Further reading
Bernstein, I.Leonard (January 2000). "Is the use of benzalkonium chloride as a preservative for nasal formulations a safety concern? A cautionary note based on compromised mucociliary transport". Journal of Allergy and Clinical Immunology. 105 (1): 39–44. doi:10.1016/S0091-6749(00)90175-1. PMID 10629450. Remsen, K. A.; Black, M. J. (19 April 1980). "Rhinitis medicamentosa". CMAJ. 122 (8): 881–884. PMC 1801634. PMID 6154514. Adams, H. Richard (2013). "Adrenergic Agonists and Antagonists". In Riviere, Jim E.; Papich, Mark G. (eds.). Veterinary Pharmacology and Therapeutics. pp. 125–56. ISBN 978-1-118-68590-7.