We also are subject to violence from normies at a pretty appalling rate, which is no doubt a factor. Losing our housing as a consequence of being institutionalized and then discharged w/o housing as part of a discharge plan probably plays a role, too.
To the OP: I know my first response was kind of flip, but in all serousness, your question as (I assume) intended would be damn difficult to operationalize. No one “dies from schizophrenia”. You may attribute this deliberate suicide and that delusional leap-from-96th-floor to schizophrenia — anecdotal tales and news stories you’ve read — but how the heck would you get a data set that could really answer your question?
In fact, operationalizing “schizophrenia” as the indepedent variable is fraught with its own problems: does the opinion of one doctor constitute sufficient reason to classify a person as a schizzy or a depressive? How about the folks who have at various times been dx’ed as one and then later the other? Unlike, say, hypercholesterolemia or congestive heart failure, the diagnostic criteria are notoriously fuzzy.