Heroin is an opiate base drug used as powerful pain relief. Unfortunately it also caused euphoric high which is highly addictive. Due to its physical withdrawal after 8-12 hours of stopping the drug, it cause dependence syndrome(addiction) which is life-long with period of abstinence(stopping drug for several months) and relapses(going back to drugs again). It is easy to stop taking drugs if the person is in Pusat Serenti or in jail, but will relapse again when he goes back to an environment when drug is available, even if the person has a strong will power. Many had tried by staying in treatment centers for extended period of time or working in remote areas where drug is difficult to get. Unfortunately almost all of them will relapse again because the craving for drugs(drug hunger) will overwhelmed their will power.
The brain makes its own opiates, the endorphins and the enkephalins. But when the brain is exposed to outside sources of opiates the brain responds by shutting down these natural opiates. There is growing evidence that heroin may actually damage the coating around the nerves, called myelin. This can slow down communication between nerve cells.