I think you're misreading his comment. His latter proposition pretty clearly implies causation: "The more time you spend on it, the worse you feel [if you're a

I think you're misreading his comment. His latter proposition pretty clearly implies causation: "The more time you spend on it, the worse you feel [if you're already unhappy]". It certainly limits the domain, but that's about as clear about causation as one can be when speaking colloquially.