Substance addiction means being addicted to drugs or alcohol, stuff that you can put into your body to change the chemistry of it. Behavioural addiction is centred around being addicted to activities. Gambling, sex, and playing video games are all things people can become addicted to. Substance addiction can cause more physical problems as you are putting toxins into your body whereas behavioural addiction only has psychological effects but can lead to physical issues such as self-harming and suicide.