Drug addiction can have various effects on the body, depending on the type of drug being abused and the severity of the addiction. Some of the physical effects of drug addiction may include changes in appetite, weight loss, malnutrition, cardiovascular damage, liver damage, respiratory problems, infectious diseases (such as HIV and hepatitis B and C), neurological damage, and increased risk of certain types of cancer. In addition to the physical effects, drug addiction can also cause social, emotional, and psychological problems, including relationship issues, financial problems, depression, anxiety, paranoia, hallucinations, and cognitive impairment.