TheStatutoryApe said:
I think you have it a bit backwards. Gambling addicts focus on winning.
OK, quoting from the Journal of Gambling Studies (

)
Findings. There were significant differences between responses of problem and social gamblers. A significant interaction indicated that social gamblers became more aroused in reaction to winning than losing, whereas problem gamblers became equally aroused in response to both tasks. Conclusions. The results suggest that it may be responses to losing, rather than winning that are paramount to the development and maintenance of problem gambling.
http://www.springerlink.com/content/gqx4821810575751/
To put it more carefully, the key is the anticipation of reward. This is what gambling machinery is geared to exploit with its flashing lights, bells, jackpot clanking, etc. It is about generating a continual impression of near misses.
So for most of us, a loss is a loss - an unrewardingly painful experience that means it would be wiser not to continue feeding the slot.
But for a problem gambler a loss is instead a near miss. Painful, but oh so close, so one more spin. A win if it comes is almost just a vague relief rather than a jolt of excitement. Anticlimactic compared to the agony of expectation.
See also...
It is certainly beyond dispute that when problem gamblers enter the losing phase they "chase" losses.[53] This involves continuing to bet in order to win so as to recoup earlier losses. Pathological gamblers can continue to gamble in the face of the most distressing anxiety. This is because they learn to associate the distress of losing with the anticipation of the subsequent powerful reward of winning.[54] As one writer explains:
"A partial and random reinforcement schedule ... is the most powerful behavioural conditioner. A typical casino-gambling game is just that - a partial - and random-reinforcement game where rewards occur with irregular frequency."[55]
http://www.knowodds.org/grip.html