Increased strain on the liver, which puts the person at risk of significant liver damage or liver failure. Seizures, stroke, mental confusion and brain damage. Lung disease. Problems with memory, attention and decision-making, which make daily living more difficult.
The more a person uses a drug the more they develop both a physical and psychological dependency to a drug. For example; those who smoke cigarettes have a hard time quitting due to psychological dependency (thinking they need one after they eat or that they do not feel good when they do not smoke) they have developed, and physical dependency (craving cigarettes) and a tolerance as the abuse goes on, when abusing a substance you develop a tolerance and have to consume more in order to feel the way you felt the first time.
