My cousin has the following symptoms: no appetite, times of nausea during which he feels he has a short hallucination followed by a let up of the nausea; his doctor has prescribed omeprazole and promethezine. He says these drugs have not stopped these symptoms. He feels less nausea when he eats something. He says he also gets heart palpitations when he has the nausea/hallucinations. He does not have the same level of nausea all of the time. Any thoughts about what could be happening to him?