Hello, Yes, Adderall can cause harmful interaction with Celexa. If taken together Celexa may increase the side effects of Adderall such as agitation, nervousness, anxiety, restlessness, and racing thoughts. Combining these medications can also increase the risk of a rare but serious condition called the serotonin syndrome which is characterized by confusion, hallucination, convulsion (fits), increased blood pressure & heart rate, fever, excessive sweating, muscle stiffness, tremor, motor in coordination, stomach cramp, nausea, vomiting, and diarrhea. In its severe form it, may cause coma and even death. She must consult her treating doctor for alternate effective drugs or to adjust the dose of these medications to prevent the harmful interactions. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Mohammed Taher Ali