Personally, I think it far more likely a medical problem such as a bolus/partial obstruction, than psychological, so I'd merely confirm with her that she knows it's something to avoid when readily avoidable, then book her in for a doctor consultation.
Please please please get her to a psychiatrist........ I can only speak from my experience. There may be something psychologically wrong or it may be a bolus. In which case a medical doctor can help.
Does she see this as a problem that needs solving? (If she does not, then educating her is your first step imo.)
However, there might be some medical concern beyond her control, worthy of a doctor consultation.