When taking an ssri antidepressant (citalopram), could mania-like symptoms be seen in a person who is not bipolar? what else could cause this?

Absolutely: Diagnosis a disease based on a medication side effect that provokes a reversible manifestation in a percentage of patients is bass-ackwards practice, though we see this happen. Bipolar is presumed to be a life-long disorder - and a serious one at that - 2nd opinions and psychological testing is often very wise. It is often overdiagnosed and meds for it can b more dangerous than ssris.

Manic-like?: Depends on what you mean by manic-like symptoms. Frequently depression is the first episode for someone who is bipolar. Antidepressants can cause "cycling" into a manic episode unless also treated with a mood stabilizer. I see from your medication list you are also on Adderall (dextroamphetamine and racemic amphetamine) which could also cause "manic-like" symptoms. Please discuss this with your psychiatrist.