Drugs are chemicals. Different drugs, because of their chemical structures, can affect the body in different ways. In fact, some drugs can even change a person's body and brain in ways that last long after the person has stopped taking drugs, maybe even permanently.
Depending on the drug, it can enter the human body in a number of ways, including injection, inhalation, and ingestion. The method of how it enters the body impacts on how the drug affects the person. For example: injection takes the drug directly into the blood stream, providing more immediate effects; while ingestion requires the drug to pass through the digestive system, delaying the effects.
Most abused drugs directly or indirectly target the brain's reward system by flooding the circuit with dopamine. Dopamine is a neurotransmitter present in regions of the brain that regulate movement, emotion, cognition, motivation, and feelings of pleasure. When drugs enter the brain, they can actually change how the brain performs its jobs. These changes are what lead to compulsive drug use, the hallmark of addiction.
More deaths, illnesses and disabilities stem from substance abuse than from any other preventable health condition. Today, one in four deaths is attributable to illicit drug use. People who live with substance dependence have a higher risk of all bad outcomes including unintentional injuries, accidents, risk of domestic violence, medical problems, and death.
The impact of drug abuse and dependence can be far-reaching, affecting almost every organ in the human body. Drug use can:
Weaken the immune system, increasing susceptibility to infections.
Cause cardiovascular conditions ranging from abnormal heart rate to heart attacks. Injected drugs can also lead to collapsed veins and infections of the blood vessels and heart valves.
Cause nausea, vomiting and abdominal pain.
Cause the liver to have to work harder, possibly causing significant damage or liver failure.
Cause seizures, stroke and widespread brain damage that can impact all aspects of daily life by causing problems with memory, attention and decision-making, including sustained mental confusion and permanent brain damage.
Produce global body changes such as breast development in men, dramatic fluctuations in appetite and increases in body temperature, which may impact a variety of health conditions.
Effects On The Brain
Although initial drug use may be voluntary, drugs have been shown to alter brain chemistry, which interferes with an individual's ability to make decisions and can lead to compulsive craving, seeking and use. This then becomes a substance dependency.
All drugs of abuse - nicotine, cocaine, marijuana, and others - effect the brain's "reward" circuit, which is part of the limbic system.
Drugs hijack this "reward" system, causing unusually large amounts of dopamine to flood the system.
This flood of dopamine is what causes the "high" or euphoria associated with drug abuse.
Loss of Self-Control
Nearly 4 percent of pregnant women in the United States use illicit drugs such as marijuana, cocaine, Ecstasy and other amphetamines, and heroin1. These and other illicit drugs may pose various risks for pregnant women and their babies. Some of these drugs can cause a baby to be born too small or too soon, or to have withdrawal symptoms, birth defects or learning and behavioral problems. Additionally, illicit drugs may be prepared with impurities that may be harmful to a pregnancy.
Finally, pregnant women who use illicit drugs may engage in other unhealthy behaviors that place their pregnancy at risk, such as having extremely poor nutrition or developing sexually transmitted infections.