I don't experience any positive symptoms, why should I take medication ?

I have had 3 episodes of psychosis each lasted about 2-3 weeks, to me they all had a clear triggers, drugs use, drug withdrawal, stress and sleep deprivation....the last psychiatrist diagnosed me as having schizophrenia and told me I should keep taking medication for the rest of my life.....but between those episodes I don't have any positive symptoms, I might have negative symptoms but they could as well be depressive symptoms and ADD.... In 13 years I have suffered a total of about 6-7 weeks of psychosis, why should I suffer the side effects of the medication and my quality of life greatly diminished just for relapse prevention ? Why should I not just take medication when I am in active psychosis ? I wonder if this last psychiatrist did not misdiagnosed me as most people here seem to loose their sanity without medication.

I am now medication free for months since the last episode and feel alot better then while I was being on them.