You became addicted to alcohol and drugs in two ways: physically and psychologically. Substances like alcohol, cocaine, amphetamines, and opium cause both physical and psychological dependence. Some like cannabis, LSD, and PCP cause psychological dependence even though they are not physically addicting (Frances, & First, 1998).
Dependence is the side effect of drugs and alcohol that results in drug seeking behavior. Your brain and nature never made the extremely powerful, toxic, and highly concentrated substances that can now be purchased and put in your body. When laboratory animals can electrically self-stimulate brain pleasure centers, they do so rather than eating or drinking and they ultimately die of thirst and starvation. Once addicted, humans devote every waking moment to getting the substance, using it, looking forward to the next time, and feeling bad about the last time. They develop severe psychological symptoms and harmful physical consequences (Frances, & First, 1998).
Physical addiction occurs because the human brain is skilled at adapting to new chemical environments. When exposed to drugs or alcohol, your brain adjusts by gradually modifying the number, configuration or sensitivity of nerve receptors for that substance. In this way your brain develops tolerance to the drugs which is a protective mechanism that allows it to become accustomed to the level of the drug you are putting in your body. For example, the first dose of heroine has an intense effect on brain cells. Higher and higher doses are required to achieve the same effects because of increased tolerance. Many drugs, such as alcohol, amphetamines, cocaine, nicotine, opiates, and anti-anxiety medication result in tolerance and therefore higher and higher doses are required to get the same high or effect (Frances, & First, 1998).
When using the same amount of drug or alcohol over time, the high eventually falls flat due to increasing tolerance to the substances in your brain. In an attempt to get the same high back, the individual increases the amount used and the frequency of use. For example, they increase the amount drank at one sitting from two drinks to six drinks, and they shorten the interval between drinking from every six hours to every three hours. The brain once again compensates and develops a higher tolerance to the effects of the larger amounts of alcohol and the other drugs. And, the cycle repeats with the individual consuming larger amounts more frequently.
Going through withdrawal and maintaining abstinence results in a return to lower tolerance levels for drugs and alcohol in your brain. Decreased tolerance means your body now behaves like a non-using adult. If you return immediately to your prior high level of use, you can experience severe side effects including; unconsciousness, respiratory distress, and even death. You no longer have a protective mechanism against high doses. You are at extremely high risk if you suddenly choose to use at high levels again (Frances, & First, 1998).
In addition, you may have sustained physical damage to your body during your previous use. You may be at a higher risk of negative effects if you return to using because your organs such as the liver, heart, and lungs are damaged from your past use of drugs or alcohol at high levels. Your physical health is poorer than it was when you first tried drugs and alcohol. If you choose to use again, you need to take precautions or you will suffer serious harm.
Overdose is a high risk if you use drugs and alcohol following a prolonged period of abstinence. If your drugs are illicit (i.e. from the street), they will have varying levels of purity and often contain mixtures of multiple drugs. This means you never really know what you are getting. You don’t know the strength or dose. So if you do choose to use, take care of yourself and use extreme caution.