It's the nature of depression though Gwiniel. To quote Blink 182, "I laughed the loudest, who'd have known?"
In some cases, yes... but it isn't depression = suicide. I'm not gonna kill myself and am diagnosed with "medium" recurrent depression. Dunno the correct English terms thus used the word medium... because it's not minor or really bad... but kinda in the middle of depression scale.
That's why I was really surprised about the news... then again I had no idea he had drinking/drug problems as well. Nevertheless, just wanted to point out depression doesn't equal as suicide although it can increase its possibility.