Was he? Do you have evidence that he was regularly taking his medication? Or that he was addicted to it? Or consuming it in quantities not prescribed (illegally)? Do you have any evidence at all to back up what you're implying?
According to the report, prior to the shooting Zimmerman had been prescribed Adderall and Temazepam, medications that can cause side effects such as agitation and mood swings, but in fewer than 10 percent of patients
http://taylormarsh.com/blog/2012/05...-drugs-also-cited-in-weeks-prior-to-shooting/