7 Types of Substance Use Disorders and Their Key Characteristics

Substance use disorder (SUD) involves uncontrollable use of a substance, typically alcohol or drugs, despite harmful consequences. Over time, SUD can lead to a disruptive daily life and cause distorted thoughts and behaviors.

Although there are many resources available to treat this disorder, one of the most common obstacles is the lengthy time it often takes away from the person’s life while they’re in rehab. But times have changed, and there are other ways to get help outside of a traditional rehab program. For instance, a partial hospitalization program in Los Angeles or a similar city allows patients to live a somewhat normal life while also getting the care they need to quit using.

Are you unsure if you or your loved one is struggling with an SUD? Discover the key characteristics of the 7 types of substance use disorders below.

1. Opioid Use Disorder (OUD)

Opioids activate the brain and spinal cord receptors, causing pain relief and pleasure. It’s not surprising that using these drugs leads to addiction. Short-term side effects like drowsiness, confusion, and respiratory depression can occur. Long-term use disrupts brain function, builds tolerance, and leads to physical dependence. 

Withdrawal symptoms, like restlessness and mood changes, peak within 24–48 hours and subside in about a week. Post-acute effects, such as depression and anxiety, may persist for months.

2. Alcohol Use Disorder (AUD)

Excessive alcohol consumption coupled with loss of control indicates the presence of AUD. Heavy drinking harms the heart, liver, and pancreas and raises cancer risks. Continuing down this path can lead to severe mental health issues and negative behaviors.

When reaching for that next drink, consider its impact on your body. Your heart, liver, and pancreas will suffer, and this increases the risk of cancer. Consider solutions like medications, rehab, and group programs such as AA.

3. Nicotine Use Disorder (NUD)

Nicotine is present in tobacco and is an addictive substance. Trying to kick the habit can be a real challenge, thanks to its compelling nature. 

Do you find yourself reaching for a smoke as soon as you wake? Or do you battle anxiety waiting for that next nicotine hit? Then you might be dealing with NUD. It’s not only a physical struggle, but nicotine grabs hold of the brain, making it a challenge to quit because your mind tries to convince you that you need the substance to survive.

According to the CDC, over 16 million Americans have diseases related to smoking. It remains the number one cause of preventable disease, disability, or death in the US, and it’s possible to quit with the help of a qualified professional.

4. Stimulant Use Disorder (STUD)

Stimulants, like cocaine, methamphetamine, Ritalin®, and Adderall®, boost dopamine levels in the brain. This increase gives you feelings of pleasure, satisfaction, and motivation. It’s a slippery slope. 

Misuse can have serious side effects, such as elevated heart rate, dilated pupils, increased blood pressure, or even chills or vomiting. All these side effects could be signs of misuse.

5. Sedative Use Disorder (SUD)

Sedatives decrease brain activity, suppress the heart rate, and slow breathing. They are often prescribed for anxiety and sleep disorders, but tolerance will develop over time, meaning you need more to notice the effects. 

Long-term consequences are unknown, but you may notice slurred speech, poor concentration, confusion, dizziness, and dependence. Ceasing use quickly can trigger life-threatening complications, including seizures. To quit sedatives, get professional advice.

6. Hallucinogen Use Disorder (HUD)

Hallucinogens are drugs that alter perception, including what you think, see, feel, or hear. They cause hallucinations — sensations, sounds, and images that seem real, though they are not. The effects, referred to as “trips,” can come on within 20 to 90 minutes and last up to 6 to 12 hours.

Research indicates that hallucinogens mess with the chemicals in your brain and spinal cord, like serotonin and glutamate. You may experience increased heart rate, nausea, elevated blood pressure, or body temperature. You might lose your appetite, experience dry mouth, or struggle with sleep. Other side effects include clumsiness, sweating, and feelings of paranoia.

7. Marijuana Use Disorder (MUD)

Marijuana is derived from the cannabis plant. Most people consume it via smoking, vaping, or even eating. The main compound, THC, is mind-altering and can be addictive. Users may experience a euphoric ‘high,’ altered mental health, and distorted thinking. Use can impact judgment, sensory perception, and motor skills. The effects vary based on potency, consumption method, and individual tolerance.

You may be experiencing MUD if you notice you are using more than intended or if you are experiencing cravings for marijuana. Other warning signs of addiction include the inability to stop using it even if it harms your relationships, school, job, health, or finances.


There is no cure for substance use disorders, and addiction may involve relapses. Getting treatment early is essential for an SUD. Whether you’re motivated by external factors or self-driven, treatment is effective at any stage. 

Individualizing treatment is crucial, as addiction is unique to each person. What works for one may not work for others. Treatment plans should adapt to changing needs over time. 

Are you or someone you know struggling with substance abuse disorder? Consider reaching out to a healthcare professional for guidance and support as soon as possible.