Generally - marijuana / cannabis has been strongly linked to increased risk and faster onset of schizophrenia / psychosis for some portion of the population. See the research here:
Yes - there seems to be one compound Cannabidiol (CBD) in marijuana that seems to be helpful for some symptoms of schizophrenia - and companies are developing drugs that provide this chemical and are testing it to see how it works. Early trials have been positive but its still early.
Just smoking marijuana / cannabis with higher levels of CBD or taking CBD oil is not likely to be a reasonable option. The amount you have to smoke / take - is very high and the cost would be something like $300 a day at current rates - to get the amount you need. So don’t waste your time on this.
My recommendation - is watch for the clinical trials by GW PHarma and see how it goes. If this works, it will likely be covered by insurance.