Drug addiction often starts as an experimentation with the use of a substance. If the feeling experienced satisfies the person, he may try it again. After a few times using a particular substance, the person begins to become addicted psychologically and physically. The need for a greater amount of drug and a higher strength increases as the addiction becomes worse, MayoClinic.com reports. The "high" does not happen like it used to. Trying to end the drug use can cause a person to feel ill; this is called withdrawal.
Opiates
The most common opiates abused include oxycodone, codeine pills and heroin. Users typically inject or ingest heroin. They may rub heroin into their gums, swallow it or snort it. Codeine and oxycodone users can crush the pills for snorting or melt them down for snorting, or take them orally. Some people use opiates or opioids illicitly to treat chronic pain, but many addicts use them for the sense of euphoria they gives. As the person continues using opiates, the body becomes accustomed to it in the system, which creates a need for continually larger doses. Signs of use and addiction include a decreased ability to feel pain, sedation and needle marks from intravenous self-injection.
Cocaine and Methamphetamine
These drugs classify as central nervous system stimulants. Users either inhale cocaine as a powder or smoke the crystallized version known as crack. Doctors may prescribe methamphetamine for such conditions as attention deficit/hyperactivity disorder, but people also buy it as an illicit substance. Signs of use and addiction of these types of stimulants include talking fast, trouble sleeping, irritability, feeling paranoid, increased pulse rate and blood pressure, a decreased appetite and loss of body weight.
Marijuana
Marijuana is a chemical substance known as tetrahydrocannabinol or THC, MayoClinic.com states, which people smoke in a pipe or in hand-rolled cigarettes called joints. It gives the person a sense of euphoria and causes increased relaxation to the point of the person having a decreased sense of his surroundings. Using this drug on a daily basis indicates addiction. Signs and symptoms of use include problems with coordination, high blood pressure and pulse rate, slow reactions to situations and reddened eyes.
Barbiturates
Barbiturates, classified as central nervous system depressants, give the person a decreased sense of their surroundings. Examples of these drugs include amobarbital and secobarbital. Users take them by mouth. Doctors typically prescribe them to help relieve stress and anxiety. Signs and symptoms of addiction include slurred speech, confusion and impairment of memory, MayoClinic.com states.
Benzodiazepines
Benzodiazepines, too, classify as central nervous system depressants and considered tranquilizers, MayoClinic.com indicates. People take these drugs in pill form, typically prescribed by doctors to alleviate anxiety symptoms. They cause the person to feel a decreased awareness of their surroundings. Examples of these drugs include lorazepam, clonazepam, chlordiazepoxide and diazepam. Such symptoms as slurred speech, confusion and impairment of memory may occur because of benzodiazepine use and abuse.
