What happens if you take bipolar medicine but are not bipolar?

That depends on the medication you're taking. "Bipolar medicine" implies a mood stabilizer, like Lithium, Depakote® or another anti-seizure medication, or one of the atypical antipsychotics, like Seroquel®, rather than antidepressants. None of these medications is used exclusively in the treatment of Bipolar disorder.

If you don't have bipolar disorder, schizophrenia, anxiety or a sleeping disorder, you will probably experience at least some side-effects of the medication without receiving much benefit. You may or may not feel less aggressive, overall; you may or may not experience cognitive (thinking) difficulties; you may or may not experience weight gain; you may or may not feel sedated or sluggish. There are a host of other, more transient, side-effects that vary by medication.

Sudden discontinuation of a mood stabilizer by someone who's really bipolar can lead to a relapse in symptoms, potential for reduce efficacy (effectiveness) when restarted, and possibly a long recovery period.

If you've been diagnosed bipolar, but simply disbelieve the diagnosis, be aware that this type of denial is very common. If you're questioning your doctor's assessment, please discuss your concerns directly with him or her.