Addiction means not having control over engaging in certain activities or substances and becoming dependent on them. Anything can potentially be addictive over time, including drugs, alcohol, sex, gambling, and certain behaviors. There is no single cause of addiction. Regularly partaking changes a person mentally and physically, and some people enjoy these changes and crave repeating them. Addiction causes unpleasant withdrawal symptoms if the substance or activity is not engaged in, continuing the cycle. Addictions can spiral out of control as more is needed to satisfy cravings.