I think oppression can contribute to a variety of disorders. I am a firm believer that 90% of mental disorders can be overcome naturally and through prayer without the use of anti-psychotics and other medications. I've known several bi-polar people. One was a christian, but was the surface type that just seemed to go through the motions. Like she had been indoctrinated into it and never left her own choice about it. Another guy I knew who had it really bad. I tried talking to him about Jesus, but he didn't really respond to it. He would just change the subject. He was molested for years by his step mom as a kid though, so this may have adversely affected his potential faith in anything divine.
I think signs of oppression are especially evident in people who fall into major depression for prolonged periods of time, especially those who don't have due cause to do so. I think it can also be the direct cause of most, if not all, anxiety disorders. I came up with a theory once, that angels and demons were capable of influencing emotional states, just by their presence alone. If they are in charge of principalities and powers and so forth, then why couldn't lessor demons be in charge of certain emotions, and while in the presence of said demon, it would adversely affect it's host. Scientist would argue that chemical imbalance would disprove the demonic influence theory, but that's not entirely true.
From the little bit that I have studied, it's evident that extreme emotional states can have adverse long term affects on chemical imbalance, even if there was no imbalance prior to that state. Take me for example. I have a major anxiety disorder, and sometimes when I am stressed really bad, I have strings of panic attacks. During a panic attack your blood is overloaded with adrenaline which in turn causes a release of chemicals like dopamine in your brain. If drugs like meth that have this same affect can damage these receptors, then why couldn't one too many panic attacks also do the same thing, resulting in a chemical imbalance?
This imbalance could also lead to other disorders such as depression and bi-polar disorder. This is all just speculation on my part. I'm not a scientist and have only studied the affects of these disorders on personality so I don't know that much about how chemicals are effected. But what I do know is that after being in a bad car accident, I developed an acute case of PTSD some months afterwards and was hospitalized because I was hallucinating and my blood pressure wouldn't come down at all. It took five days to get it back to normal, from just one episode of PTSD, which is really just a severe panic attack that lasts a long time. So that just proves that it's true that traumatic or extremely emotional events can cause permanent damage.