Considering that most experts agree that environmental factors can contribute to the development of mental illness, then I would say yes. People who are intellectually and morally corrupt can contribute to mental illness in people who are affected by their negative behaviors. For example, I believe that most wars were started by people who were intellectually and morally corrupt. Soldiers who come back from those wars with PTSD probably wouldn't have ever had those issues if it weren't for intellectually and morally corrupt leaders, whichever side of the fence you think that falls on. Many times, people who have developed mental illness were abused as children or even in their adult life. I suppose that would be another example.
I believe the current theories are that, for many mental illnesses, there is a combination of biological environmental, and sometimes physiological factors involved in the development of mental illness. Still, some leading neuroscientists believe that it is completely biological/physiological. The question of explaining why twins separated at birth, experiencing different levels of nurture and care, yet developing the same mental illness comes to mind. Also, one must wonder why some who use drugs or experience horrors in their lives develop mental illness while others do not. It seems safe to say that there must be at least some biological factors at play.
I believe you mentioned drugs and I believe you are trying to insinuate that it is moral and intellectual corruption on the part of the individuals who suffer from mental illness that causes them to do so. Considering that you focus on schizophrenia, this doesn't surprise me. I'm sure you've heard stories of how someone smoked marijuana and that "kick started" their illness. However, even the experts who list this as a causing factor, state that it is an issue for someone who is already genetically predispositioned. Who is to say that they didn't decide to use drugs because they were trying to self medicate for issues they were already having and made it worse instead? Who is to say that six months later they wouldn't have encountered an extremely stressful situation and ended up in the same place? As far as I'm aware, there is no hard proof that this even occurs.
If you are saying that people with mental illness have brought it upon themselves by being intellectually/morally corrupt, then I fail to see how you can say that you are "friends" with people suffering from schizophrenia. That would be like visiting a burn unit and comforting patients and then leaving and discussing how they brought it upon themselves by not being cautious enough.
Furthermore, I would assume that you're aware that even children can develop mental illness. Would you suppose that is because they are intellectually/morally corrupt? Do you also believe that everything bad that ever happens to anyone is some sort of cosmic punishment?
The roots of mental illness