Exciting news! CURA4U is now offering online urgent care consultations in 50+ states across USA. Click here to learn more!
For Physicians
Sign Up 0    

Substance Use Disorder


Substance use disorder (SUD), commonly known as drug addiction, refers to the condition in which a person persistently uses illicit drugs despite knowing that they are harmful and have adverse effects. The disorder affects a person's brain, leading to thoughts, perceptions, and behaviors that compel him to use the drug, and he has no control over this compulsion. This substance abuse results in several mental, emotional, social, and physical adverse effects, like guilt, aggression, irritability, joblessness, family and relationship issues, liver cirrhosis, impaired immunity, endocrine disturbances, neurological problems, skin problems, etc. Common drug classes used in SUD include alcohol, tobacco, opioids, cannabis, phencyclidine, and other hallucinogens, inhalants, sedatives, hypnotics, stimulants, etc.

This disorder results due to the interplay of both genetics and environmental factors. Environmental factors like stress, trauma, relationship complications, job or study difficulties, low socioeconomic status can cause this disorder in genetically susceptible patients. It is also found in people with co-occurring mental illnesses like anxiety, depression, post-traumatic stress disorder


The exact cause of the disorder is unknown. It is thought to be a result of both genetics and environmental factors;

  • Genetics: family history plays a role. If you have a parent or sibling with the same disorder, you might suffer from it too. Children of parents who have used drugs may have a high risk of developing the disorder due to genetics and environmental influence. 
  • Environmental: environmental factors may include the amusing effects of the drug itself, peer pressure, stressful life, low self-esteem, social issues, low socioeconomic status, emotional distress, etc.  
  • Co-occurring mental disorders: psychological disorders like anxiety, depression, post-traumatic stress disorder, attention deficit disorder, or other mental illnesses can make a person susceptible to drug abuse. Such people may feel the rewarding effects of these drugs more comforting and supportive, making it more likely for them to continue its use. 

The use of a substance is usually started by occasional intake due to peer pressure, followed by regular use, ultimately leading to a high use up to a level of addiction. 

Risk Factors

Following risk factors may increase your chances of getting a disorder;

  • Family history
  • History of other mental disorders
  • Other chronic illnesses can cause stress and difficulties with life.
  • Facing social problems like Abusive spouse, broken family, being poor, etc.
  • Social gatherings or friends using substances
  • Suffering a trauma, like a war or childhood abuse.


In 2017, 5.5% (271 million)of adults were estimated to have used one or more illicit drugs worldwide. Out of which, 35 million people had a substance use disorder, resulting in 585,000 deaths in 2017. About 4% of the American adolescent population reported a substance use disorder in 2017. And approximately 1.8% of adolescents ( 443,000 -age 12 to 17) had an alcohol use disorder.

Drugs Types

Drug classes used commonly include:

Alcohol: Alcohol is the most commonly used substance. It depresses the brain functions, thus causing the disinhibition of normally inhibited behaviors seen in drunk people. 

Opiates: Opiates and other narcotics are strong painkillers doctors usually prescribe for severe pain. But for the effects caused by them, like drowsiness, feelings of euphoria, well-being, happiness, joy, and excitement, they are used in SUD. Other drugs of this class include heroin, codeine, opium. 

Stimulants: Stimulants include amphetamines and cocaine. They are used to treat ADHD, an attention deficit disorder usually found in children. They act by stimulating the brain. But because they can make a person feel high and excited, they are used in SUD. 

Depressants: this class includes barbiturates, chloral hydrate, benzodiazepines that reduce anxiety and cause drowsiness. Increasing amounts are needed to produce the same effect leading to addiction to these drugs. 

Hallucinogens: PCP, also called "angel dust,” Marijuana, cannabis, and LSD, are also widely used as SUD. They cause hallucinations and other addictive symptoms.


When a person starts using these drugs, he finds it impossible to live without them.  Although he is aware of the multiple side effects of the drugs, he continues to use them contrary to the opposition by the family or the circumstances. Failed attempts are made to stop the drug, and upon stopping, withdrawal symptoms occur. This phenomenon is called substance dependence. Over time, Increasing amounts of drugs are used to produce similar effects known as substance tolerance.  The symptoms can be due to the substance use disorder or the effects of the drugs used. The signs that point towards the SUD are;

  • Changes in behavior: Irritation, agitation, fearfulness, being secretive, school and work absences, complaints from the school or workplace, change of appetite and sleep patterns, personality changes, lack of motivation
  • Physical changes: Deteriorating physical appearance, lack of cleanliness, red eyes, small pupils, weight loss or weight gain, slurring of speech, impaired coordination, tremors, hyperactivity, drowsiness. 
  • Social changes: Change of friends circle, hobbies, facing legal problems, getting driving tickets, financial issues, needing money all the time, stealing, relationship problems.


A substance abuse patient can come to the clinic for the complaints related to the drug used, can especially come for help and support to stop the drugs, or can present in the emergency department due to drug overdose. Each case needs a particular and different approach, with history, examination, and toxicology screen (Blood, urine, or other lab tests to find the presence and quantity of drugs) being the common denominators. Psychological or psychiatric assessments must be done for such patients. 

Most of the time, patients underestimate their consumption. They will deny the excess use and consider themselves as occasional users. The doctor will especially ask questions about the frequency and amount of the drugs used.

The doctors use a special questioning technique called CAGE questions;

C – Have you or anyone ever felt you should cut down on your drinking?

A – Have you ever felt annoyed by people for criticizing your drinking?

G – Do you feel guilty about your drinking?

E – Do you feel the need for an eye-opener in the morning to get rid of a hangover?

One positive answer to the above questions is considered suggestive of the SUD. Two or more positive responses are indicative of the disorder. 


Substance use disorder is difficult to treat. Patients are pretty stubborn and deny their addiction. Those who stop often restart using the drugs again. 

  • Efforts are made to slowly withdraw the drug or stop it abruptly; the resulting withdrawal symptoms need to be managed in a hospital or home. The withdrawal symptoms commonly experienced are tremors, body pain, diaphoresis, tachycardia, anorexia, insomnia, diarrhea, abdominal cramping, rhinorrhea, and Seizures. 
  • When the drug is stopped altogether, along with medical and social support, it is called detoxification. Sometimes different medicine with the same effects is replaced and then stopped slowly. 
  • It is very important to stay drug-free (abstinence). Extreme support is needed for emotional and physical symptoms. 
  • Con-current mental health disorders need to be diagnosed and treated.
  • Therapies play an important role. Behavior, group, family therapies, cognitive behavioral therapy, etc.
  • It is very beneficial to join support groups easily available in the community. E.g., Narcotics Anonymous, Alcoholics Anonymous


Prognosis depends upon how well the case has been handled. Although treatment is complicated, people can have drug-free periods leading to complete cessation with proper support and medications . 


 “Prevention is better than cure.” This phrase works well in every case, especially drug addiction. We all must adopt healthy life habits and strategies to prevent suffering from substance use disorder.

  • Learn to manage stress and pressure
  • Seek help before using a drug for any condition or situation bothering you
  • Try to avoid temptation and accompany good people 
  • Seek treatment for mental illness
  • Keep a healthy and well-balanced life
  • If you have a family history of drug addiction, stay away from drugs as much as possible.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 30, 2023.


NIMH » Substance Use and Co-Occurring Mental Disorders (nih.gov)


Psychiatry.org - What Is a Substance Use Disorder?