Substance Use Disorder

What are substance use disorders? 

Substance use disorder (SUD), also known as drug addiction, is a disease affects a person’s brain that can have life-long and life-altering consequences. Substance use disorder occurs when a person has no control over the use of a certain substance or substances, despite knowing about and experiencing the harmful consequences. With substance use disorder, a person becomes addicted or dependent on the substance, and no matter how hard a person tries to quit or wants to quit, it is extremely challenging and causes significant distress or impairment in daily functioning.

Prolonged use of certain substances can change the brain (permanently in some cases) in ways that make quitting or having a high quality of life nearly impossible. Substance use often requires lifelong treatment and multiple layers of supports. Substance use disorder is a powerful and complex disease that is often life-threatening. Substance use disorder is the leading cause of preventable and early death. The earlier you seek help, the better the treatment outcomes.

Drugs that can lead to addiction

  • Opioids (pain killers such as heroin, fentanyl, oxycodone, hydrocodone, codeine, and morphine)
  • Alcohol
  • Club drugs (GHB, ketamine, MDMA (ecstasy/molly), flunitrazepam (Rohypnol®))
  • Stimulants (cocaine or methamphetamine) 
  • Hallucinogens (ayahuasca, D-lysergic acid diethylamide (LSD), peyote (mescaline), phencyclidine (PCP) and DMT))
  • Inhalants (solvents, aerosol sprays, gases, and nitrites (poppers))
  • Marijuana
  • Prescription drugs and cold medicines
  • Sedatives, hypnotics, and anxiolytics (anti-anxiety medications)
  • Steroids (anabolic)
  • Synthetic cannabinoids (K2 or Spice)
  • Synthetic cathinone (bath salts)
  • Nicotine/tobacco, electronic cigarettes, vaping
Once a person starts using these substances and becomes intoxicated, repeated use over time eventually begins to change the brain. Substances affect the reward center of the brain, activating dopamine responses (massive surges), which gives the brain and body an overall sense of pleasure. Humans are biologically motivated or driven to seek rewards. Over time, with continued usage, the brain develops a tolerance for the substance, and it takes larger amounts to become high or intoxicated.

Eventually, chasing the feeling of being high becomes the all-consuming task in life. The cravings and dependency intensify, and quality of life is significantly impacted. Many people who are deep in substance use believe they cannot function without the substance. SUD can be life-threatening. 

Signs and Symptoms

There are several signs or symptoms that a person is suffering from a substance use disorder (SUD). Signs and symptoms include:

  • Bloodshot eyes
  • Looking tired
  • Changes in appetite (usually eating less)
  • Craving the substance
  • Changes in personal hygiene or appearance
  • Difficulties in occupational, academic, social settings, or other important areas of functioning
  • Unstable relationships
  • Increased engagement in risk-taking behaviors (unprotected sex or driving while under the influence)
  • Financial problems
  • Inability to limit or control substance usage
  • Unexplained weight loss
If you or your loved one have any of these symptoms, consult with your healthcare or mental healthcare provider. The best treatment outcomes result from early detection or prevention. 


There is no singular cause for substance use disorder. Generally, SUD develops due to a combination of factors. The main factors that contribute to developing SUD include:

  • Genetics. A family history of substance use disorder can be a predictor of SUD, although it does not necessarily guarantee that SUD will develop. Some people have a genetic predisposition for addiction. Additionally, some genes may speed up or delay the progression of the disease.
  • Environmental factors. Specific beliefs, values, and behaviors that are demonstrated in your household or by important caregivers may influence choices related to substance use. Additionally, peer groups may heavily influence choices and behaviors surrounding substance use. Having a trauma history may also increase your risk of developing SUD.
  • Psychological factors. Mental health conditions may significantly increase the risk of developing SUD due to using substances to cope with certain symptoms.
  • Brain changes. Once a substance is used over time, the brain starts to change and develops a tolerance for the substance, requiring a larger amount or more frequent use of the substance to experience the high. The brain’s tolerance for the substance grows into a greater dependency, which significantly impacts daily functioning.

Risk Factors

There are several risk factors that may contribute to an increased risk in developing SUD. Risk factors include:

  • Family history of SUD. Research has found genetic linkages to SUD. If you have a parent or sibling that has SUD, you are at an increased risk of developing SUD if you choose to use an addictive substance.
  • Mental health condition. Several mental health conditions can feel overwhelming and have distressing symptoms. Some people use substances to cope with the overwhelming thoughts, feelings, or behaviors. Depression, anxiety, and PTSD are some examples of mental health conditions that are more common to also have a diagnosis of substance use disorder.
  • Peer pressure. Being influenced by peers or social media plays a huge role in increasing the risk of developing SUD, especially in young people.
  • Early usage. The younger a person is when using an addictive substance, the more likely it is to alter or change brain development, which increases the risk of developing SUD.
  • Lack of family involvement. Research has shown that the lack of a secure or safe bond with a primary caregiver, absent or uninvolved parents, or difficult family situations or dynamics can lead to an increased risk of developing SUD. 
  • Using a highly addictive drug. Certain drugs may result in a faster development of addiction, which increase the likelihood of developing SUD. Stimulants and opioids tend to become addictive much faster than some other substances. Additionally, smoking, or injecting substances can lead to a faster development of addiction.


Substance use can have many short-term and long-term complications, some of which are life-threatening. Complications include:

  • Certain drugs are extremely dangerous when taken at higher doses or when combined with alcohol (methamphetamines, cocaine, and opioids; GBH and flunitrazepam; MDMA (molly/ecstasy); street drugs that can be laced with dangerous unknown substances; inhalants)
  • Developing an infectious disease (through sharing needles or unsafe sex)
  • Other health problems
  • Family problems
  • Accidents
  • Suicide
  • Financial problems
  • Work-related issues
  • Academic issues
  • Legal issues


Diagnosis for SUD can only happen when the person acknowledges that there is a problem, and they seek help for it. If you consult with your healthcare provider, they will take a thorough medical history and may ask questions about your mental health. Your doctor will conduct a physical exam and will most likely order tests, screenings, and labs to assess for substance use and rule out any other medical condition. Additionally, if substance use disorder is suspected, your doctor will refer you to a mental health provider.

A mental health provider will conduct a thorough intake, gathering information about presenting problems, symptoms, substance usage, family medical history, mental health history, and relationship dynamics and social engagement or support. They may do more specific assessments for substance usage and addictions. If your mental health provider suspects SUD and specializes in addictions, he or she may continue treatment with you. However, if they do not specialize in addictions, or if the substance use disorder has progressed to a more severe level, you may be referred to inpatient care, or a residential treatment facility. 


Treatment for SUD is a long and enduring process. It impacts not only the individual, but also family and friends. It is a challenging condition to treat, often having times of relapse and recovery, only to relapse again. There is no cure for SUD, but the goal for treatment is to enter a recovery phase and remain in recovery for the rest of your life.  
There are several forms of treatment for SUD. The most common forms of treatment are detoxification, medication-assisted therapy, and psychotherapy. However, if the substance use is severe enough, it may result in hospitalization, or it may be recommended to go to an inpatient or outpatient rehabilitation center.

There are also various other self-help or rehabilitation programs that focus on recovery and maintaining sobriety (Alcoholics Anonymous and Narcotics Anonymous, or Al-Anon and Nar-Anon family groups). More specifically, treatments include:

  • Detoxification. This form of treatment is when you stop using the substance and allow it to get fully out of your system. This can be an extremely challenging process and may require healthcare supervision for safety purposes. Sometimes, when detoxing, medications are used to help alleviate some of the cravings and symptoms of withdrawal.
  • Medication-assisted treatment. Maintenance medications are one of the most effective treatments for SUD. Studies have shown a reduction of substance use as well as a reduction in negative outcomes related to SUD. 
  • Psychotherapy. Cognitive behavioral therapy (CBT) is the most effective and recommended therapy in dealing with substance use. This type of therapy can help challenge distorted patterns of thinking and negative beliefs and replace with more adaptive ones. CBT also helps to build coping skills. Your mental health provider may also recommend other treatment modalities and may encourage patients to join a therapy group for addictions. 
  • Hospitalization, inpatient, or outpatient rehabilitation facilities. Some cases that are more severe may result in hospitalization. Once stabilized, it may be recommended to try an inpatient or outpatient rehabilitation program. 

The path to recovery from SUD is a long and enduring process, but well-worth the investment, both in the short-term and long-term future. If you or a loved one struggles with SUD, please consult with your healthcare provider to figure out next steps on the road to recovery.