Gambling, in this context can be considered drug addiction in that every role of the dice, spin of the wheel or scratch of a lotto ticket sends endorphins rushing through the system.
Drug abuse affects the way the brain experiences pleasure.
Drugs make people "high" by invading and manipulating the brain's pleasure circuitry and bombarding the nerve endings with our bodies own natural medications (in the form of endorphins). They fool your brain into good feelings that are a reaction to chemicals, instead of to real experiences. They will also numb the system to the point where "feeling normal" is painful.
The key word is "fool." Drugs can damage the brain's wiring for pleasure, making it unable to function in a healthy, normal way. You can become addicted, meaning that your craving for the feeling you get from a drug will become so strong that you'll risk serious consequences to get it. And your ability to feel pleasure the old-fashioned way—the real way—may be disrupted.
Good food, real accomplishments—even true love—may leave you feeling flat.