Anti-Moodiness

How do you instantaneously get someone out of a sorrowful gloomy mood?

Ask him, sincerely, to explain something very few people other than him understands. Make it like you want to know. Convince him it's urgent that he breaks it down - right away.

This will put him in 'expert' mode, his mind tells the body to stop moping, and the adrenaline rushes back in.

Depression cannot 'breathe' in such circumstances.