A worst-case scenario for a player can arise due to "tilt" in poker, aka a losing streak magnified by negative emotions. From another review paper [1]: "Tilting is defined as “a strong negative emotional state elicited by elements of the poker game (e.g., “bad beats” or a prolonged “losing streak”) that is characterised by losing control, and due to which the quality of decision-making in poker has decreased” [...] After a significant loss, tilt occurs in three phases: (1) a dissociative phase (disbelief, “unreality,” unwillingness to “accept” the events), (2) a phase of indignation and negative emotions (feelings of injustice and unfairness), (3) and the chasing phase."
Since real money can be at stake, especially if a young person starts to play poker online, the consequences can be far worse than for a person who develops an unhealthy relationship with chess. Though a research review paper suggests that these worst-case scenarios do not happen to the majority of young poker players, it can still happen to a significant number of them.