To understand “addiction hijacks brain” first have to understand “addiction” and “brain”.

What is Addiction:

Word “Addiction”, is originated from Latin term which means “enslaved by” or “bound to’.  It refers to the condition of being imprisoned to practice something that is psychologically or physically habit-forming, as narcotics, to such an extreme that it can cause destruction of person and his loved ones to massive level. Addiction is a strong and harmful need to regularly have something (such as a drug) or do something.



The human brain is the most complex organ in the body. This three-pound mass of gray and white matter sits at the center of all human activity. The brain is made up of many parts that all work together as a team to perform basic functions. Different parts of the brain are responsible for coordinating and performing specific functions. Drugs can alter important brain areas that are necessary for life-sustaining functions and can drive the compulsive drug abuse that marks addiction.

Addiction and brain:

Drugs are chemicals that tap into the brain’s  communication system and disrupt the way nerve cells normally send, receive, and process information. There are at least two ways that drugs are able to do this: by imitating the brain’s natural chemical messengers, and/or over stimulating the “reward circuit” of the brain.

Some drugs, such as marijuana and heroin, have a similar structure to chemical messengers, called neurotransmitters, which are naturally produced by the brain. Because of this similarity, these drugs are able to “fool” the brain’s receptors and activate nerve cells to send abnormal messages.

Other drugs, such as cocaine or methamphetamine, can cause the nerve cells to release abnormally large amounts of natural neurotransmitters, or prevent the normal recycling of these brain chemicals, which is needed to shut off the signal between neurons. This disruption produces a greatly amplified message that ultimately disrupts normal communication patterns.

Nearly all drugs, directly or indirectly, target the brain’s reward system by flooding the circuit with dopamine.

The primary system in addicts’ brains that’s physically different than those of non-addicts is the brain’s “Reward System.” The primary neurotransmitter that stimulates the Reward System is called dopamine. Drugs over-stimulate the Reward System by increasing dopamine many more times than natural rewards. In turn, the brain reacts defensively to the overstimulation by developing tolerance, which results in physical changes to brain cells in the Reward System. These changes alter not only the structure of those neurons, but also their function, changing the way the brain operates and how addicts think. Chronic exposure to drugs of abuse disrupts the way critical brain structures interact to control and inhibit behaviors related to drug use.

Maryam Riaz
Clinical Psychologist
Willing Ways, Islamabad