However, most addictive behavior is not related to either physical tolerance or exposure to cues. People compulsively use drugs, gamble, or shop nearly always in reaction to being emotionally stressed, whether or not they have a physical addiction. Since these psychologically based addictions are not based on drug or brain effects, they can account for why people frequently switch addictive actions from one drug to a completely different kind of drug, or even to a non-drug behavior. The focus of the addiction isn't what matters; it's the need to take action under certain kinds of stress. Treating this kind of addiction requires an understanding of how it works psychologically.