(((Eleanor))) I've never seen this listed as a side effect for Citalopram but that doesn't mean it's not possible as we all react differently to meds. Do you recall when you started having the nightmares and the last change made to your meds at that time? Perhaps it's one of your other medications? I agree with CANDC, it needs to be addresses as soon as possible so that you don't become sleep deprived. You could also call your pharmacist to check out the side effects of all your meds if you can't get a hold of your prescribing physician. Best wishes