Drug use or abuse crosses the line into drug addiction when you feel you have to have the drug, and you increase the amount of the drug you take. Various factors, such as your personality, your genetic makeup and peer pressure, affect your likelihood of becoming addicted to a drug. In addition, some drugs, such as heroin and cocaine, more quickly produce a physical addiction than other drugs do for many people.

Physical addiction appears to occur when repeated use of a drug alters reward pathways in your brain.

The addicting drug causes physical changes to some nerve cells (neurons) in your brain.

Neurons use chemicals called neurotransmitters to communicate. Neurons release neurotransmitters into the gaps (synapses) between nerve cells; neurotransmitters are received by receptors on other neurons and on their own cell bodies. The changes that occur in this communication process vary with the type of drug to which you’re addicted, though researchers have discovered that addictive drugs, such as cocaine and morphine, affect some areas of the brain in the same manner. If further research confirms findings such as this, it would be possible to develop more effective medications to combat addiction to more than one drug.

Drugs Mechanism

Cannabis compounds

The main active agent in cannabis compounds, delta-9-tetrahydrocannabinol (THC), affects the neurotransmitter communication process. Some people perceive the effects of THC as enjoyable, and this sensation reinforces use of the drug. For others, THC causes uncomfortable feelings or anxiety, which doesn’t reinforce use of the drug.

Central nervous system depressants

Benzodiazepines and barbiturates produce long-term cellular changes partly by enhancing the actions of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Released into the synapses, GABA binds to receptors and ultimately lowers cell excitability, which slows down brain activity.

Central nervous system stimulants

These drugs raise the levels of dopamine and serotonin in the synapses. Brain cells release dopamine as part of the reward system through which you learn to seek stimuli, such as food and sex. Serotonin is a chemical in the brain that regulates mood. Stimulants block the reabsorption of dopamine after its release and can physically alter the sensitivities of some dopamine and serotonin receptors.


These drugs affect the nerve cells of the reward pathways in your brain in ways similar to that of stimulants, producing positive reinforcement for the use of these drugs. There are opioid receptors in the brain, spinal cord and gastrointestinal tract.

Sources: healthygenius

No related content found.