It means that you are already an addict for you to allow gambling to be a threat to your peace of mind. This is the main reason why one needs to gamble responsible and stay healthy to avoid being addicted to gambling. Assuming, there is nothing like addiction and only losses when gambling, nobody will see gamblers as irresponsible people because they are still in control of your senses. Addiction takes over all your thinking mentality.
Peach of mind is the after math of every action, if your peace is taken you should know that something ha e triggered it to go, such as unbearable loses and pressure to meet certain amount to recover, this can become a worrying point that affects your overall peace of mind and could because a dip threat as far as addition is concerned, so you are very correct that the mate who's is an addict already will definitely be the one to exhibit such tendency of emotional imbalance.