I do get the impression hes often depressed. I know depression horrible and can debilitate anyone but he strikes me as someone who'd use it to behave like a right moody prick.
A lot of people with debilitating depression act as if everything is fine. This when suicide for no apparent reason is such a shock. My son's friend was the life and soul of the party, he had a wide circle of friends, but not one of them knew the torment he was going through. Nor did I. I saw him the morning of the day he died, and he was his usual cheerful self, chatting about his job, the festivals he was planning to go to that summer, told me tell my son he'd see him at the weekend, remarked on what a beautiful day it was - absolutely no sign of any inner turmoil or distress. An hour later, he'd left the world, leaving a detailed note as to why dying was preferable to living.
My personal theory (and it
is only mine) is that people who are miserable constantly, aren't actually clinically depressed, they are just unhappy and fed up.