Once again referring to Elder Holland’s talk from the Saturday afternoon session of General Conference, he mentioned that George Albert Smith suffered from depression. I’m fairly well versed in Church history, but didn’t realize how sever it was until I followed some links online. Apparently while an apostle he had a 3-year battle that at times saw him rarely leave his bed. He seemed to hit rock bottom, and then he started to get a bit better, and ultimately became President of the Church.
Jana Reiss at Religion News Service has a great summary of his struggles, as well as a link to a Journal of Mormon History article that has more details.