Addiction is a brain disease. One of the manifestations of drug addiction is the loss of the ability to think rationally. An addict craves, seeks and uses drugs even in the face of depressing circumstances such as troubled relationships, financial debts, problems at work, and even physical incapacities.
The craving for drugs is a psychological need which can only be satisfied with the “high” that only drugs can satisfy. The degree of addiction to drugs is mainly dependent on the innate nature of the body to react to the increasing dose and frequency of using drugs. Your body’s biology will often dictate the degree and intensity of how one person reacts to the chemical substances. It is hard to understand how one person will react to a drug compared to another person because some people are sensitive to the chemistry of substances and others are not.
The constant want and use of drugs despite of all the problems and bad consequences which can possibly arise from the addiction are indications that an individual has a compulsive behavior which is psychologically rooted to a need for drugs.