I found an article in the Mennonite World Review this morning stating that the Amish have a higher incidence of bipolar disorder than the general population.
This topic has been researched by Abram Hostetter, a world recognized psychiatrist, since 1976.
The group Hostetter has been researching in Lancaster County actually have a lower incidence of mental illness than the general population, but a higher occurrence of bipolar disorder.
Research in this specific group is particularly important because of the genetic factors of bipolar disorder. The Lancaster County Amish have a documented pedigree of people that originated with the 32 that immigrated there in the 1760’s, and there has been little marriage outside of this group, forming a closed gene pool.
On top of that, the Amish community prohibits the use of drugs and alcohol that often mask the symptoms of bipolar disorder, making the disorder more readily apparent for study.
Currently the research team is working on genetic coding based characteristics from each manifestation of the illness, and have detailed medical histories and genetic information for over 100 people with bipolar disorder.
For more information, you can read the full article here.