Addictions have historically been defined by substances that lead to destructive behaviors in pursuit of the next fix. However, as technology has improved, f-MRI data along with mounting evidence suggests that behavioral addictions are more like substance addictions than initially believed; addiction resides not in the properties of a substance but the interaction between those properties and a person's vulnerability to addiction. A wide variety of behaviors can induce an addiction-like state that scientists debate where to draw the line between a coping mechanism, a symptom of another disorder, and addiction.