oh, this is an interesting question ^^;
Something that I've researched a lot is how physical and mental disorders affect/cause each other. There actually isn't much difference between the two, I think. The mind/nervous system determines the overall chemical balance of the body after all, so an imbalance in neurotransmitters can cause detrimental physical effects over time. Physical illness, too, leads to emotional stress and so can undermine mental health.
I grew up in an abusive environment with my schizophrenic mother, so started experiencing heavy stress from a young age. The first signs of illness in me were mental, I was diagnosed with PTSD and depression at age 6 and OCD at age 8. Soon after, at age 9, I became very ill with autoimmune disorders. It's taken the rest of my life up to now for me to learn how to repair what was damaged, but via my research I've been able to find a road to healing by approaching the overall problem from both medical and psychological directions.
I believe that in general hardship presents an opportunity for growth. When faced with an obstacle, one can either fall into despair and give up, or learn how to overcome it and therefore become wiser in the end. My illness has caused me a great deal of suffering, at some times I've been bedridden for months, and at worst incapable of coherent cognition. It has challenged my sense of self and even my will to live at times, caused me to fail others and threatened my most important relationships and dreams. But it has also inspired me to learn and grow. On the journey to healing I've learned a great deal about integrative medicine, herbology, analytical psychology, and the particulars of the human system and how to care for it as a whole. I've grown in acceptance and compassion for others, recognizing the inevitability of human frailty and being able to not only resonate with suffering, but to understand why it happens the way it does. This understanding has freed me from biased judgements of others, allowing me to experience a greater and more stable depth of love for them. I think, even though it's been difficult, and even though I wouldn't choose to suffer as I have, I'm thankful for the experience and how it has made me a better person in the end.