5 Signs of Drug Addiction in Adults

Medically reviewed by Dr. Mark Hrymoc, M.D.

Addiction is a brain disorder in which a person continues misusing drugs despite encountering harmful consequences. There are at least five signs of drug addiction in adults that make it clear someone has a problem with prescription or illicit drugs. The most common signs include mood or personality, behavior, appearance, relationship, and physical health changes. 

If you or someone you know is displaying signs of drug addiction, it may be time to reach out for help and explore the benefits of addiction treatment.

Drug addiction is a nationwide problem, with 48.7 Americans over twelve having a substance use disorder (SAMSHA). Some adults have an addiction to prescription or illicit opioids, and others are addicted to alcohol, cocaine, marijuana, methamphetamines, and numerous other products. Addiction negatively impacts someone’s personal, professional, academic, and social life.

In this article, we explore five common signs of drug addiction in adults so you can know when it is time to seek help.

Signs of Drug Addiction in Adults

Drug addiction in adults can manifest in various ways, often subtly creeping into daily life until it becomes a significant issue. It might begin with increased tolerance, where more substance is needed to achieve the same effects.

Behavioral changes such as withdrawal from social activities, neglect of responsibilities, and secretive behavior are common indicators. Physical signs might include changes in appearance, unexplained health issues, or erratic sleeping patterns.

Psychological signs are also telling, with mood swings, anxiety, or depression frequently accompanying addiction. Recognizing these signs early is crucial for timely intervention and recovery.

Here are the most common signs of drug addiction in adults.

1. Changes in Mood or Personality

Adults develop unique personalities and moods. When you describe someone, you likely use adjectives that describe their personality. Funny, grumpy, short-tempered, laid back, and friendly are just a few examples.

Signs of addiction in adults include changes in their mood or personality. Someone who was once friendly and outgoing may now prefer to isolate themselves. Someone easygoing may become argumentative and aggressive.

Other mood changes may include:

  • Difficulty holding back anger and lashing out aggressively.
  • Overreactions to situations, likely because they misread the situation. 
  • Lack of impulse control even in risky situations.
  • Difficulty making decisions and solving problems.
  • Poor memory and forgetfulness.
  • Depression, anxiety, bipolar disorder symptoms.
  • Paranoia or hallucinations.

2. Changes in Behaviors

Drug misuse and addiction make people behave in ways they would not if they were sober. One reason is that drugs alter how neurotransmitters communicate in the brain. Behavioral changes you may see include skipping school, work, or social events.

They may disappear for long periods without telling anyone where they are going. Depending on the drug they misuse, a person may become clumsy and have trouble with motor skills.

Signs of drug addiction in adults may also include lying and stealing to finance their drug addiction. They engage in risky behaviors, like seeking drugs in dangerous areas of town. Driving while intoxicated, domestic violence, and other criminal activity may become part of their need to maintain their addiction. Their addiction takes priority over everything else.

3. Changes in Appearance

Personal hygiene and changes in appearance are noticeable signs of addiction in adults. Drugs become more important than daily hygiene, trendy clothing, and the latest hairstyle. The following are common changes in appearance related to drug addiction:

  • Tooth decay due to drug use and lack of oral hygiene.
  • Unusual odors on their breath.
  • Clothing smells like smoke and the drugs they use.
  • Hair may look unclean or messy.
  • Hair loss.
  • Weight changes.
  • Track marks, abscesses, or collapsed veins from needle injections.
  • Burns or soot on fingers.
  • Wounds are slow to heal.
  • Chapped lips.

Various drugs lead to damaged skin, whether with acne breakouts or self-inflicted wounds from picking the skin. Drug misuse can also lead to dark circles under the eyes, rashes, dry skin, uneven skin tone, and wrinkles. Heroin, cocaine, and methamphetamine are known for killing skin cells altogether.

4. Changes in Relationships

Drug addiction interferes with all relationships, including those at home, work, school, and social. Signs of drug addiction in adults include avoiding meetings, family activities, romantic dates, classes, and social functions to spend more time using drugs.

Addiction changes how people communicate. Couples often find themselves arguing. Addiction destroys trust with those who feel betrayed, like employers, teachers, friends, and family.

Money problems become a primary source of division in families because a person with a substance use disorder spends money needed for daily living on drugs. Doing so puts the entire family at risk of being without food and shelter.

Other issues in relationships may include a lack of trust, abuse, enabling, and codependency.

5. Changes in Physical Health

Physical health changes can appear at the beginning of someone’s drug addiction, including having little energy, appearing exhausted, slurred speech, and slower movements.

Someone misusing opioids may nod in and out of consciousness, while someone misusing cocaine may have nose bleeds or sniffles. Someone on methamphetamines perspires a lot, so much so that their clothing will be wet.

The signs of drug addiction in adults become more physically noticeable as time goes on and may include:

  • Seizures that become more frequent.
  • Frequent illnesses due to weakened immune system.
  • Liver disease, such as Hepatitis C.
  • Gastrointestinal disorders, like reflux or pancreatitis.
  • Heart problems, such as arrhythmias, low blood pressure, or cardiac arrest.
  • Respiratory issues, like pneumonia or acute respiratory distress.
  • Progressive kidney damage requiring dialysis or transplant.

Get Help Today

Are you or a loved one experiencing one or more of these signs of addiction in adults? The path to recovery starts with a single, crucial step – reaching out for help.

The Mental Health Center in Los Angeles specializes in connecting you with mental health professionals who understand the complexities of addiction and provide addiction treatment plans tailored to your individual needs.

Imagine a life free from addiction’s hold, with a treatment plan designed specifically for your unique situation. This personalized approach increases the likelihood of successful, long-term recovery.

Don’t wait for tomorrow. Contact the Mental Health Center in Los Angeles to start your journey toward addiction recovery today.


Addiction changes all parts of a person’s life, and understanding the signs of drug addiction in adults can help you seek the best treatment. Not everyone will exhibit the same signs, but personality, behavior, appearance, relationship, and physical health changes can be easier to identify than others. 

Treatment is available for everyone, whether their addiction is new or has been ongoing for years. You can find the best program for your needs. Call us today to connect with a provider who understands the signs of addiction in adults.