The brain is an important part of our body. There are billions of neurons present in our brain in different centers to control different parts of your body. Like a group of neurons control digestive system while another group controls nervous system. There is a mutual cooperation between all these neurons that makes a man look wise and effective. The limbic system in a brain helps a person to process information and memory, learn new things and even motivating the person. Any disorder in working of any system results in mental illness.
Drugs which help to cure mental illness or affect brain are called psychopharmacological agents. These may be the cure to anxiety, depression, psychosis, manias, hallucinations, etc. These may be helpful for medical purposes but possess many side affects which even includes addiction of these drugs. These drugs tend neurons to release large amounts of neurotransmissions. Thus the person under these drug-affects does not have any control on his senses. Some drugs appear to provide mental relaxation or incredible amount of energy thus slowly resulting in addiction.
It is better to use drug testing kits to check addiction and control them.