As a gambler it's important to know how to control your emotions and discipline yourself, not just in the aspect of gambling but in every other area of life. Emotional instability caused by depression can lead to a whole lot of regretful actions. Gambling when you are having mixed emotions can cloud your judgment and also affect the decisions you make, at that point you wouldn't mind if you are losing and you can keep going till you have nothing left all under the excuse of chasing your losses. I have had some experiences where I decided to gamble when I was emotionally down and I regretted my actions. Some cases are actually a psychological issue where gamblers knowingly try to make themselves sad by ruining their financial life consciously, this is rare but it happens. Don't engage in gambling when you are depressed, if you are looking for a distraction try to do something productive instead.
It is true and I believe that when you gamble during depression you get emotional and it becomes very difficult to control yourself. When someone is not depressed, money management works in him and when money management is not working in him, no matter how rich he is, he will not be able to hold on to his wealth. Many people gambled during their depression and drunkenness and then they made huge losses. A gambler must always take care of these things if he does not want to suffer financially
Not to everyone, some people gamble better when they are depressed. Our emotions might have nothing to do with how we gamble, how and when we gamble can even become what to cheer us out from certain depression. Depressions at different level, majorly stress can be treated while gambling but financially dealing with depression becomes very wrong to gamble in such a state, the mind will be controlled by excessive want of profits and the gambler may not know how to control his emotions causing a more severe loss.
Drunkenness' is a whole different level, the gambler is totally not in control of his mind, what ever he does at that moment isn't important, everything he does are not coming from right senses and are unthoughtful, anyone high on any substance should avoid any activity that requires spending money.