Post-traumatic stress disorder and anorexia nervosa in a patient with chronic arsenic poisoning: a case report and review of literature

We presented the case of a 33-year-old female referring to the ward of gastroenterology for progressive diarrhea, darkening of skin, edema, and numbness in bilateral lower limbs. She had a history of a persistent self-administration of bisacodine and Chinese medicine (Bezoar Antidotal Pill, which contained microquantity of As203 and As205) for weight loss and an excessive preoccupation with weight. Experts in consultation-liaison psychiatry made a diagnosis of Anorexia Nervosa (AN) in the first interview, while the inconsistence between the self-negligence of skin color (delay medical treatment until convinced her physical condition is life-threatening) and the excessive preoccupation with weight remained to be puzzling. And further biopsychosocial interview revealed a history of Post-Traumatic Stress Disorder (PTSD) which made the clinical manifestations much more rational (delayed presentation was a combined effect of AN-related denial and PTSD-driven generalised avoidance, with PTSD exacerbating the pre-existing AN-related delay). We explored the epidemiology of AN, and offered a review of current literature on the comorbidity of ED and PTSD, including the pathogenesis and current treatment conception of the two diseases. Notably, this case represents a rare triple comorbidity of AN, PTSD, and chronic arsenic poisoning secondary to use of arsenic-containing traditional medicine for weight loss, which posed substantial diagnostic and therapeutic challenges in a liaison psychiatry setting.