While specific incentives differ from person to person, generally speaking, people start using drugs to escape or mask pain. In some individuals, the onset of drug use can be from untreated psychiatric issues, including anxiety and depression. The rush of pleasure from using drugs can provide temporary solace from suffering, which can stem from much mental health or other issues, including the following: Trauma or abuse Mental illness Low self-esteem Poverty Relationship problems Loss of a loved one Stress Chronic pain or medical conditions But whatever their reason for starting, once addiction sets in, the disease usually spirals more and more out of their control. The sad truth is that more deaths, illnesses, and disabilities are caused by substance abuse than by any other preventable health condition. Prolonged drug dependence interferes with just about every organ in the human body, and while different drugs have different damaging effects, these are some of the common conditions substance abuse can cause: The damaged immune system, which increases susceptibility to infection Cardiovascular conditions, including heart attacks and collapsed veins Nausea, vomiting, and abdominal pain Liver overexertion or liver failure Seizures and strokes Widespread brain damage that can interfere with memory, attention, and decision-making, as well as permanent brain damage Some of the worst effects of substance abuse aren't even health-related. Drug abuse can have a number of damaging consequences on an addict's social and emotional well-being, including: Loss of employment Relationship loss Incarceration Financial trouble Homelessness Risky sexual behaviour Many problems can be reversed or minimised by getting sober, but there may be some health and emotional issues that simply won't heal with time. The best way to prevent permanent damage is to seek professional drug addiction treatment ASAP to overcome the addiction.