Common Types of Drugs and Their Effects

Drug addiction affects millions of people across the United States and the rest of the world every year. The substances used may vary, but the end result is feeling like you don’t have control over your life and wondering whether there’s any hope for a better one. 

The good news is that recovery is possible, and there are many treatment options available for those who are ready to seek help. Whether you’re struggling with substance use yourself or are concerned about a loved one, learning about the most commonly used substances and how drug addiction works can help you recognize when there’s a problem.

While most people use the term “drug addiction,” healthcare professionals refer to it as a substance use disorder (SUD). Clinicians diagnose substance use disorder based on factors like whether a person’s attachment to a specific substance interferes with their ability to function reasonably, how much of a substance they use and whether they continue to use despite negative consequences. 

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) classifies the severity of SUDs based on how many of its 11 criteria are met, with a minimum of two required for a diagnosis. These include:

• Continuing to use a substance without regard to risks
• Substance use that negatively affects relationships
• Favoring substance use over regular responsibilities
• Experiencing withdrawal symptoms
• Developing a tolerance to the substance
• Increasing the frequency or amount of use
• Feeling a lack of control over substance use or an inability to stop
• Spending more time acquiring or using the substance
• Experiencing negative physical or mental health effects because of use
• Avoiding hobbies or regular activities to use
• Having cravings that impact quality of life

Clinicians generally look at substance use within the past year when determining whether a diagnosis is appropriate. Substance use disorders are classified as mild (2-3 criteria), moderate (4-5 criteria) and severe (6+ criteria).

Healthcare professionals often conduct a mental health evaluation as part of substance use disorder screening, especially if it’s part of the intake process at a rehab. This assessment can identify any co-occurring mental health disorders that may impact recovery or need to be addressed as part of a comprehensive treatment plan. When your treatment plan includes protocols for both substance use disorder and a mental health disorder, it’s called dual-diagnosis care.

Substance use affects people from all walks of life and all demographics. Anyone can develop a drug dependency and need treatment. Understanding how common substance use is can help those seeking treatment feel more comfortable reaching out for help.

According to the 2024 National Survey on Drug Use and Health (NSDUH) from the Substance Abuse and Mental Health Services Administration (SAMHSA) and data from the National Center for Drug Abuse Statistics (NCDAS):

• More than half of people aged 12 and older have used an illicit substance at least once in their lifetime.
• 16.7% of those aged 12 or older have used illegal substances in the past month.
• Almost 37% of high school students have used an illicit substance by their senior year.
• Marijuana and opioids are the most commonly used substances after alcohol.
• More than 100,000 people die from drug overdoses every year in the United States.
• One-third of people with a mental illness also had a substance use disorder. 
• Among those aged 12 and older, 18.2% needed treatment for substance use disorder, but only 3.5% received it.

These statistics show how common substance use is and underscore the need for quality treatment programs. 

Although the terms are often interchanged, there’s an essential distinction between drug misuse (also called drug abuse), drug dependence and drug addiction. Drug misuse refers to any situation where someone is using illicit drugs or they’re using a prescription or over-the-counter (OTC) medication outside medical direction. Using Benadryl to help you sleep a few times a week is an example of drug misuse because it’s not specifically intended to address sleep issues.

When a person’s body and brain start to adjust to the regular use of a substance, they can develop a tolerance and, eventually, dependence. The key signs of drug dependence are needing more of the substance to get the same effect and experiencing withdrawal symptoms. These withdrawal symptoms indicate the brain and body have become dependent on the substance to function normally.

When someone continues to use a substance even when they’re experiencing negative consequences, they likely have a substance use disorder (addiction). Even though the person may be fully aware of risks, they feel out of control and unable to reduce or stop using on their own. 

Substance misuse can happen with everything from illegal substances and prescription drugs to OTC meds and common household chemicals. The list below includes some of the most commonly misused drugs, with usage patterns based on 2024 SAMHSA data. 

Marijuana

Marijuana (cannabis) is the most commonly misused substance other than alcohol. Synthetic marijuana also falls into this category. While the federal government still classifies marijuana as a controlled substance, it’s legal for medical use in 40 U.S. states and legal for recreational use in 24.

Marijuana use has been linked to mental health concerns, such as depression and anxiety. It can affect everything from how quickly the brain processes information to how much motivation someone has for daily life tasks.

Approximately 44.3 million people aged 12 and older reported using marijuana in the past month. The number of people who’ve used marijuana in the past year is even higher, coming in at 64.2 million, which is 22.3% of those age 12 and up. The highest rate of use (35%) is in the 18 to 25 age group, and most people are smoking (73.9%), ingesting (49.8%) or vaping (39.8%) the drug.

Opioids

Opioids are drugs that affect the connection between the body and brain by binding with opioid receptors across the nervous system. They reduce pain and increase the amount of dopamine in your body, which is what creates the high. Prescription medications, such as oxycodone, buprenorphine, methadone and fentanyl, are the most commonly used opioids, but heroin also comes up in the statistics.

Around 0.2% of people aged 12 or older reported using heroin within the last year. While this number may seem small, it accounts for more than 550,000 people across the United States. The numbers for prescription pain reliever misuse, of which prescription opioids make up 95%, are even larger. 

Approximately 8 million people aged 12 or older misused prescription pain relievers in the last year, with adults 26 or older making up the largest portion (6.6 million). The vast majority (82.8%) said they got the pills either from family members, friends or legitimate prescriptions.

Hallucinogens

Hallucinogens are named for the hallucinatory effects they create. They affect sensory perceptions, which can make people see, hear, feel and smell things that aren’t really there. Common hallucinogens are LSD, PCP, psilocybin mushrooms and ketamine. Party drugs like Ecstasy are also included in this category.

Past-year hallucinogen use among people aged 12 and older has been increasing, rising from 2.7% in 2021 to 3.6% in 2024. That’s a change of nearly 2.8 million people, with those 26 and older showing the highest increase.

Stimulants

Stimulants affect the nervous system, increasing alertness, reaction times and the ability to focus. It can also make users feel more confident and social. The impacts on your nervous system also cause changes in your body, including increased heart rate, blood pressure and body temperature and reduced appetite. Common stimulants include methamphetamine, cocaine and prescription medications like Ritalin and Adderall. 

Cocaine use was more common than methamphetamine, with an overall past-year use rate among people age 12 or older of 1.5% compared to 0.8%, respectively. Rates for prescription stimulant misuse are similar to those of cocaine, with 1.4% of individuals aged 12 or older misusing prescription stimulants in the past year. 

The largest age group misusing stimulants was adults aged 18 to 25. This statistic makes sense since college students commonly misuse stimulants as a way to increase academic performance.

Benzodiazepines

Benzodiazepines are prescription medications that act as nervous system depressants. They slow the heart rate and breathing, decrease blood pressure and have a sedative effect. Common drugs include Xanax, Valium and Ativan, which are often prescribed to treat anxiety and sleeping disorders. 

According to the NCDAS, 1.2% of Americans (3.4 million people) misuse benzodiazepines every year. However, of those who were prescribed the substance legitimately, nearly 25% report misusing it, indicating the high risk of addiction benzodiazepines carry.

Inhalants

Inhalants are substances that produce a high when inhaled repetitively or in large concentrations. Commonly misused substances are often everyday household products, such as paint and cleaning products, and aerosol products, such as spray paint and hairspray. 

Approximately 3.2 million (1.1%) people aged 12 or older used inhalants purposefully in the past year. Adolescents aged 12 to 17 report the highest percentage of use (3.7%), which is more than triple the rate for all ages.

Over-the-Counter Medications

When taken as directed, over-the-counter medications can help with minor, everyday concerns, such as a headache, heartburn or the common cold. But some people misuse OTC drugs to produce a specific effect. For example, high doses of the cough suppressant dextromethorphan (DXM) can produce a sedative effect and hallucinations.

Quantifying over-the-counter drug misuse can be challenging because the medications are legal and abuse is underreported. A systematic literature review published in Frontiers in Psychiatry found that there were widespread OTC drug misuse concerns, with the most commonly mentioned substances being DXM and diphenhydramine.

Engaging in compulsive substance abuse affects every area of your life and those around you. The drugs have physical effects on your body, and constantly riding the rollercoaster of addiction and trying to figure out where the next hit will come from takes a toll on your mental and emotional health. You may also experience problems keeping up at work or school or maintaining relationships with family and friends. 

Short-Term Effects of Drug Abuse

The short-term effects of drug abuse are the immediate physical and mental changes you may experience when using a substance. These can include:

• Changes in appetite
• Increased or decreased heart rate
• Increased or decreased blood pressure
• Difficulty breathing
• Changes in sleep quality and ability, including insomnia
• Changes in activity levels
• Mood swings
• Paranoia or panic attacks
• Nausea and vomiting
• Lack of motivation
• Uncontrollable shaking or tremors

What these short-term effects look like depends on the type of drug. For example, stimulants amp up the body, increasing heart rate and blood pressure and making you feel energized and focused. Sedatives, on the other hand, decrease your respiratory rate and make you sleepy. Every person is unique, and a substance may also have different effects based on factors like amount and length of use and whether there are any pre-existing health conditions.

Long-Term Health Complications Linked to Drug Addiction

When substance misuse happens over an extended period, lasting effects on the body may occur. Potential health complications linked to substance use disorders include:

• Hallucinations and psychosis
• Changes in heart rate or blood pressure
• Increased risk of heart disease
• Anxiety, depression and other mental health disorders
• Pregnancy complications
• Increased risk of cancer, especially when smoking a substance
• Changes in brain function, memory and cognitive ability
• Increased risk of chronic diseases, such as HIV and hepatitis
• Frequent and/or severe nosebleeds
• Increased risk of organ damage, disease or failure
• Significant weight fluctuation

As with the short-term effects of substance use, how the body responds to ongoing drug use depends on the person’s overall health and medical history. If you’re concerned about the potential long-term effects of a substance and want to learn how you can protect yourself, reach out to your doctor or a substance use treatment center.

Withdrawal Symptoms and Overdose Risk

If you’ve developed a dependence on a substance, you’re likely to experience withdrawal symptoms if you try to cut back or stop using it. Factors like age, weight, general health, type of substance used and length of use contribute to the type of withdrawal symptoms you may experience and how severe they may be.

Some of the more common symptoms of withdrawal include:

• Nausea and vomiting
• Blood pressure changes
• Depression
• Anxiety
• Mood changes
• Cravings
• Being tired or unable to sleep
• Diarrhea
• Sweating
• Tremors
• Seizures
• Aches and pains
• Appetite changes
• Confusion
• Heart rate changes

Withdrawal symptoms for some substances, such as alcohol and opioids, can be especially dangerous and require medical supervision as you go through detox. 

Any time someone is misusing a drug, there’s a risk of overdose. This risk can be especially high with illicit substances, where you can’t tell for sure what’s in the drug or how potent it may be. Signs of a drug overdose include:

• Difficulty breathing
• Severe nausea, including vomiting and diarrhea
• Extreme agitation and paranoia
• Drowsiness and extreme fatigue
• Lack of coordination
• Confusion
• Loss of consciousness

If someone is unable to be woken up or is showing any of the signs above after consuming a drug, it’s a medical emergency. Call 911 immediately. If naloxone (Narcan) is available, administer it according to the instructions. Naloxone is specifically for opioid overdoses, but it won’t hurt someone if they took a different substance, making it safe to use if you’re unsure what they may be overdosing on. 

Dealing with substance use can be extremely challenging, and it’s not always clear when someone is using substances recreationally and when they’ve developed a problem. Asking yourself these questions can help you understand whether substance use is developing into dependence and addiction:

• Do you use drugs even though you’re aware of the dangers?
• Would you rather use drugs than hang out with friends?
• Is using drugs more appealing than your daily tasks?
• Do you have withdrawal symptoms if you try to cut back on or stop using substances?
• Do you feel like you need larger amounts of a drug or need to use it more often to get the same effect?
• Does it feel impossible to stop using even though you want to?
• Are daily responsibilities and tasks harder if you haven’t taken drugs?
• Do you feel like cravings are taking over your life?

If you answered yes to any of the above questions, it could be a sign that you’re dealing with a substance use disorder and it’s time to reach out for help. 

There’s no formula for determining who’ll become addicted to drugs, but there are certain factors that can put you at greater risk. 

Age of First Use

The younger someone is when they first use drugs, the more likely they are to develop a substance use disorder. Children and adolescents are also at an increased risk of addiction because the brain hasn’t fully developed. At this stage, changes in the brain’s reward center and how dopamine and other neurotransmitters are processed can have lifelong effects.

Family History of Substance Use

Having a family history of substance use can increase your risk of addiction, but it’s not as simple as pure genetics. While researchers are still exploring whether there may be a specific “addiction gene,” family history can also impact other areas of substance use risk. 

Substance use is normalized in some families, which can potentially lead to a younger age of first use or easier accessibility of substances. Someone who’s consistently around family members using drugs may not understand the risks until they’ve already developed a dependence. 

A History of Trauma

Experiencing traumatic events, particularly as a child, can impact how likely someone is to develop a substance use disorder as an adult. A study published in the American Journal of Preventive Medicine found that those who experienced 4-plus adverse childhood events (ACEs) were 10 times more likely to have injected drugs. ACEs include witnessing domestic violence, having a family member who was incarcerated or having a parent with a substance use disorder.

Traumatic experiences in adulthood can have a similar effect. Those with post-traumatic stress disorder (PTSD) may use substances as a way to numb their emotions or to self-medicate for sleep problems or difficulties with work performance. 

Co-Occurring Mental Health Disorders

Approximately 21.2 million adults in the United States have both a substance use disorder and a co-occurring mental health disorder, per SAMHSA data. Mental health and addiction often appear together, and it can be challenging to determine which came first. 

In some cases, those with mental health disorders, especially with more serious conditions like schizophrenia, may misuse substances to self-treat their symptoms. In other cases, prolonged drug use can create mental health conditions due to changes in brain chemistry. 

If you’ve been diagnosed with a substance use disorder or are concerned about your habits, treatment options are available. What level of care is right for you depends on your addiction history and whether you have any additional physical or mental health concerns. Most people start with detox before moving into residential or outpatient treatment and then stepping down to sober living, support groups and other aftercare options. 

Drug Detox Programs

Most detox programs have medical supervision by trained healthcare providers to ensure withdrawal is as safe and comfortable as possible. Nutrition and medication management are the basis of most detox programs.

Medical detox can be inpatient or outpatient and is tailored to the results of your initial substance use evaluation. You work with healthcare providers to decide which treatment program is best for you based on the amount of drugs in your system and any current or past medical and psychological conditions. 

While not all drugs cause severe withdrawal symptoms, trying to quit on your own isn’t recommended. In some cases, such as with alcohol and opioids, it can be extremely dangerous.

Inpatient and Residential Drug Treatment

If you’ve been using drugs for a long time or at high doses or experienced withdrawal symptoms when trying to quit on your own in the past, inpatient or residential treatment is usually recommended. Both options require you to live at the facility, but inpatient rehab generally takes place at a medical facility, such as a hospital. Inpatient and residential treatment programs commonly last for 30-90 days, but longer stays are available at some rehab centers when needed.

During your stay, you may participate in individual counseling, behavioral therapy and alternative treatment modalities, such as yoga therapy or sound baths. You may also be offered support groups, group therapy, aftercare planning and relapse prevention planning.

Outpatient Programs

Outpatient programs are typically for individuals whose addiction is less severe and who have a good and stable home/support system. Outpatient care can also be a step down in a continuing care model for those who’ve already completed residential treatment. Outpatient care may be less expensive than residential treatment for those concerned about affordability.

Some outpatient programs are labeled as intensive outpatient programs (IOP) or partial hospitalization programs (PHP). These are more intensive and designed to provide inpatient-level care without requiring overnight stays. These programs often require you to take part in treatment at the center for several hours a day, every day or most days of the week.

All outpatient programs involve some combination of medical and behavioral approaches to provide a well-rounded solution and help prevent relapse. They’re typically organized in 30-day chunks, with some people needing just a few months of treatment while others continue for a year or more.

Medication-Assisted Treatment

Medication-assisted treatment may be a part of your care plan if you have an alcohol or opioid use disorder. It’s tailored to your unique needs and can help with slowly tapering off a substance or reducing withdrawal symptoms. 

FDA-approved medications to manage withdrawal symptoms or use as maintenance drugs include:

• Naltrexone
• Methadone
• Buprenorphine
• Suboxone
• Acamprosate
• Disulfiram
• Lofexidine

These medications should be used as part of a more comprehensive treatment plan in combination with behavioral therapy and other evidence-based treatments.

Support Groups

Peer support groups can be a valuable resource during the recovery journey because you get the chance to connect with others who understand what you’re going through. Connecting with those in active recovery, some of whom have been sober for several years, can help you see that long-term sobriety is possible and offer opportunities for mentorship. 

Many support groups base their programs on the 12-step approach associated with Alcoholics Anonymous. These groups include:

• Narcotics Anonymous
• Cocaine Anonymous
• Marijuana Anonymous
• Crystal Meth Anonymous
• Heroin Anonymous

There is also Al-Anon, which is for family members of those addicted to substances. Alateen is specifically for young people whose friends or family members have a substance use disorder.

Aftercare

Graduating from rehab is a huge accomplishment that’s worthy of celebrating, but it isn’t the end of the journey. Recovery is a life-long process, and it’s important to continue focusing on your sobriety. Continued substance use treatment after a formal program is called aftercare, and it can include everything from continued individual and group counseling to alumni support groups.

It’s easy to think that you can try a substance once or only use it socially or for special occasions without developing a problem. However, many drugs are highly addictive, and developing a drug dependency can happen before you realize it.

Treatment programs are available to provide the help and support you need to overcome substance misuse. If you’re ready to take the first step, reach out to RehabNet’s helpline today to speak with someone who can help you understand your recovery program options and find a rehab that works for you.