While treating women with psychotic illness, I noticed that many of my patients, in addition to their psychosis, had eating disorders (anorexia and binge eating) and I wondered whether my prescription of antipsychotic drugs was responsible. I knew that these drugs led to increased appetite and weight gain, which could provoke a counter reaction, ie, a drive to be thin.
The neuroscientist and author Erin Hawkes—who was treated for schizophrenia with olanzapine—writes about how her bulimia subsequently intensified:
I was put on olanzapine. Terrible mistake: I was, within two months, 137 pounds of (in my opinion) fat. My purging went wild. . . . Olanzapine gave me a ravenous appetite. . . . Thus, purging became all-important.1
She is not the only person to have made the connection between antipsychotic medication and increased eating disorder symptoms. Olanzapine and clozapine in particular have been implicated in medication- induced bingeing secondary to antipsychotic drug intake.2,3
http://www.psychiatrictimes.com/special-reports/eating-disorders-and-psychosis/page/0/1