Snorting cocaine can damage the interior of the nose, and smoking crack can lead to pneumonia or other lung damage. There is evidence that taking cocaine during pregnancy can lead to low birthweight babies with small heads, abnormalities in the genitalia, and mental retardation. There is some controversy about these findings, since mothers studied often had other risk factors such as other drug use, poverty and malnutrition. In a sense, cocaine trains its users to depend on it. The dependence is much more psychological than physical.
Cocaine use provides rapid, consistent, intense positive reinforcement.
When one stops using cocaine, the world is grey. But they are also less stimulating than they were before, because the reward pathway is now impaired. Most commonly, users will binge on cocaine, come down from the high, then take another and larger dose and come down again, continuing until they run out of cocaine, or until reward pathways are too depleted to respond. At this point, users become exhausted and may sleep for a long time. To numb their feelings of depression, they may use depressant drugs like heroin or alcohol.