I went to residency with a guy who was a general dentist in the army training to be a pediatric dentist. We became fast friends and we were like brothers. The nicest, kindest, most sincere human I've ever met. Fun doesn't adequately describe him. He was chronically happy, knew everyone's name in the room within the first 3 mins, was unbelievably outgoing, a dedicated father of 4, and always super positive about everything. His son had a very rare disease that required him to go to a university hospital halfway across the US for 6 months mid-residency. This was the first time I saw evidence of the cracks starting to form. When he returned he was obviously behind everyone and he needed to stay some additional time to finish his residency. He started showing up having downed cough medicine and then he was drinking or doing drugs. He converted to Mormonism at 19 (which made our friendship even less likely being an atheist) but it's now clear he did that because he was having problems with drugs/EtOH then too. I left residency and stayed in touch and he graduated and went back to the army where he was supposed to be assigned to a base where he'd be the pediatric dentist. I guess he continued to fracture and he was diagnosed with bipolar and bumped around the VA system for a few years but they could never get his meds right and he was discharged for medical reasons. It's also clear now that he was such a force of nature when I met him because he was hypomanic. He got divorced and then remarried his high school sweetheart and went into private practice. I thought he was doing well and then at the age of 35 woke up one morning at his lake house, walked down to the water, and killed himself with a gun. I had just spoken to him the week before and I had no idea. I'm pretty perceptive and to this day (12 years later) I still can't believe he's gone and that I had no idea he wasn't doing well. I cried more at his funeral than at my father's or my sister's funeral. People can be VERY good at hiding things.
It's hard when we lose people to this kind of stuff...