I do hallucinate a little when I'm not on antipsychotics, but cannabis does not seem to affect this. If you hallucinate on weed you should maybe consider smoking less or stopping completely. I would think cannabis abuse is bad for your health no matter who you are and what your diagnoses are, but I've also seen studies that show moderate cannabis use has an antidepressant effect, and that cannabis use preceding the onset of schizophrenia lessens the severity of the cognitive impairments that come with the illness.