I came within inches of an ending like this.
Depression is a very serious, insidious, bastard illness. It unravels from the inside, then tries to unravel everything around it so it won't die alone.
Rest well, Richard; I know your pain. I hope it is ended now. I hope you find the simple things we all need, but are sometimes blinded to. Be free. Be happy.
If someone you know shows sudden changes in personality, flips moods in an instant, is always either high or low and never in between, or retreats far away from the world on occasion blaming fatigue or illness or just needing a rest, or just seems "off" somehow, do something. Do anything. Call a doctor, a clergyman, a help line, family members, friends. Google "depression." Do anything.
Prepare for a fight. A fight that may avoid writing an epitaph like this one.