Overview
Drug addiction, also called substance use disorder, is a disease that affects a person's brain and behavior and leads to an inability to control the use of a legal or illegal drug or medication. Substances such as alcohol, marijuana and nicotine also are considered drugs. When you're addicted, you may continue using the drug despite the harm it causes.

Drug addiction can start with experimental use of a recreational drug in social situations, and, for some people, the drug use becomes more frequent. For others, particularly with opioids, drug addiction begins with exposure to prescribed medications, or receiving medications from a friend or relative who has been prescribed the medication.

The risk of addiction and how fast you become addicted varies by drug. Some drugs, such as opioid painkillers, have a higher risk and cause addiction more quickly than others.As time passes, you may need larger doses of the drug to get high. Soon you may need the drug just to feel good. As your drug use increases, you may find that it's increasingly difficult to go without the drug.

Attempts to stop drug use may cause intense cravings and make you feel physically ill (withdrawal symptoms). You may need help from your doctor, family, friends, support groups or an organized treatment program to overcome your drug addiction and stay drug-free.

What is drug addiction?
Drug addiction (also known as substance use disorder) can be defined as a progressive disease that causes people to lose control of the use of some substance despite worsening consequences of that use. Substance use disorder can be life-threatening. Addictions are not problems of willpower or morality. Addiction is a powerful and complex disease. People who have an addiction to drugs cannot simply quit, even if they want to. The drugs change the brain in a way that makes quitting physically and mentally difficult. Treating addiction often requires lifelong care and therapy.

What drugs lead to addiction?
Drugs that are commonly misused include:

• Alcohol, Club drugs, like GHB, ketamine, MDMA (ecstasy/molly), flunitrazepam (Rohypnol®).
• Stimulants, such as cocaine (including crack) and methamphetamine (meth).
• Hallucinogens, including ayahuasca, D-lysergic acid diethylamide (LSD), peyote (mescaline), phencyclidine (PCP) and DMT.
• Inhalants, including solvents, aerosol sprays, gases and nitrites (poppers).
• Marijuana.
• Opioid pain killers such as heroin, fentanyl, oxycodone, hydrocodone, codeine and morphine.
• Prescription drugs and cold medicines.
• Sedatives, hypnotics and anxiolytics (anti-anxiety medications).
• Steroids (anabolic).
• Synthetic cannabinoids (K2 or Spice).
• Synthetic cathinones (bath salts).
• Tobacco/nicotine and electronic cigarettes (e-cigarettes or vaping).

While these drugs are very different from each other, they all strongly activate the addiction center of the brain. That is what makes these substances habit-forming, while others are not.

How might substance use disorder affect me?
Drugs affect the brain, especially the "reward center" of the brain.
Humans are biologically motivated to seek rewards. Often, these rewards come from healthy behaviours. When you spend time with a loved one or eat a delicious meal, your body releases a chemical called dopamine, which makes you feel pleasure. It becomes a cycle: You seek out these experiences because they reward you with good feelings.

Drugs send massive surges of dopamine through the brain, too. But instead of feeling motivated to do the things you need to survive (eat, work, spend time with loved ones), such massive dopamine levels can lead to damaging changes that change thoughts, feelings and behavior. That can create an unhealthy drive to seek pleasure from the drug and less from more healthy pleasurable experiences.

The cycle revolves around seeking and consuming drugs to get that pleasurable feeling.Addiction to drugs changes the brain over time. It affects how the brain works and even the brain's structure. That's why healthcare providers consider substance use disorder a brain disease.

The first use of a drug is a choice. But addiction can develop, creating a very dangerous condition. Drugs affect your decision-making ability, including the decision to stop drug use.You may be aware there's a problem but unable to stop. With addiction, stopping drug use can be physically uncomfortable. It can make you sick and even become life-threatening.

What are symptoms of substance abuse?
Symptoms of drug addiction include:

• Bloodshot eyes and looking tired.
• Changes in appetite, usually eating less. Changes in physical appearance, such as having a poor complexion or looking ungroomed, Craving drugs.
• Difficulty completing tasks at work, school or home, Engaging in risky behaviours, despite knowing negative consequences (such as driving while impaired or having unprotected sex).
• Inability to reduce or control drug use, Issues with money, Weight loss.

What are treatment for substance abuse and addiction?
Several therapies exist for treating substance use disorder. Even for a severe case, treatment can help.

Often, you'll receive a combination of these therapies:

• Detoxification: You stop taking drugs, allowing the drugs to leave the body. You may need healthcare supervision to detox safely.
• Medication-assisted therapies: During detox, medicine can help control cravings and relieve withdrawal symptoms.
• Behavioral therapies: Cognitive behavioral therapy or other psychotherapy (talk therapy) can help deal with addiction's cause. Therapy also helps build self-esteem and teaches healthy coping mechanisms.

Medication may be part of your treatment plan. Your care team figures out the best medications for you.
Medication-assisted treatments are available for:

• Opioids: Methadone, buprenorphine and naltrexone are FDA-approved for the treatment of opiate use disorder.
• Alcohol: Three FDA-approved drugs include naltrexone, acamprosate and disulfiram (Antabuse).
• Tobacco: A nicotine patch, spray, gum or lozenge can help. Or your doctor might prescribe bupropion or varenicline.

Both inpatient and outpatient treatment plans are available, depending on your needs. Treatment typically involves group therapy sessions that occur weekly for three months to a year.

Inpatient therapy can include:
Hospitalization.
Therapeutic communities or sober houses, which are tightly controlled, drug-free environments.
Self-help groups such as Alcoholics Anonymous and Narcotics Anonymous can help you on the path to recovery. Self-help groups are also available for family members, including Al-Anon and Nar-Anon Family Groups. Participation in 12-step based recovery work has been proven to improve outcomes.