Can Playing Poker Cause Depression?
The short answer is No, at least not directly on it's own.
Hondo probably gave the best answer in the third post after your question.
Many of the other posts are really describing frustration, annoyance, bad moods or feelings and not actual depression.
Simply playing poker is not sufficient to cause depression.
Playing poker whilst already suffering depression will probably be unprofitable and contribute to the depth of depression.
It is more likely that the negative consequences of a
gambling addiction such as financial difficulty and loneliness from the obsession could lead to depression.