Author: Gulf Breeze Recovery
Last updated: August 2026
24/7 confidential admissions line: 833.551.2304
Behavioral changes can sometimes be among the first noticeable signs of substance use, even before physical symptoms become clear. These changes can vary depending on the substance involved, including opioids, heroin, fentanyl, cocaine, methamphetamine, prescription medications, and alcohol. Signs may also look different in teens and from one person to another.
When someone is struggling with substance use, it can be difficult to recognize how serious the problem has become. People may become very good at hiding their habits, especially from those closest to them. They may also have trouble seeing how substance use is affecting their health, relationships, or daily life, which can make it harder to recognize when support may be needed.
Talking with a loved one about substance use can be difficult, especially when they appear to be functioning normally. Understanding common behavioral signs of substance abuse, along with substance-specific physical and behavioral changes, can help families recognize concerning patterns and decide when it may be time to seek professional guidance.
Key takeaways
- Behavioral changes can be important warning signs, sometimes before obvious physical changes are noticed.
- Physical and behavioral signs often overlap, and they can vary significantly depending on the substance.
- One behavior by itself does not prove that someone has a substance use disorder.
- Denial can make problematic substance use difficult for both the person and their loved ones to recognize.
- When several concerning patterns appear or worsen, a professional substance use disorder evaluation can help clarify what is happening.
- Gulf Breeze Recovery offers holistic, non-12-step substance use disorder treatment for clients who are ready to seek help.
General behavioral signs of substance abuse
A person who has misused substances for some time can become good at concealing the extent of that use. People can appear to be functioning normally, but under the surface, they may have a significant issue.
Some common behavioral signs of substance misuse are:
- Poor performance at work or school
- Changes in behavior, such as a greater desire for privacy
- Spending more money than usual or asking to borrow money more often
- Changes in physical appearance
- A lack of energy in regular daily activities
- Withdrawing from friends and family
- Issues managing finances
If you’re trying to figure out how to tell if someone is on drugs, look for multiple changes that persist or become more noticeable over time. Recognizing these patterns can also help you better understand some of the common obstacles to overcoming substance use disorder.
Signs of opioid abuse, intoxication, and overdose
Opioids include prescription pain medications as well as drugs such as heroin and fentanyl. Signs of opioid abuse or misuse can develop gradually, which can make them difficult for family members or friends to recognize.
Possible behavioral warning signs may include:
- Becoming increasingly preoccupied with obtaining or using opioids
- Taking prescription opioids in larger amounts or differently than prescribed
- Mood or personality changes
- Pulling away from family, friends, work, school, or usual activities
- Changes in physical appearance or health
- Neglecting personal hygiene
If you or someone you love is concerned about opioid use, learning more about Gulf Breeze Recovery’s opioid treatment program can be a helpful next step toward understanding available support.
Read our other articles about opioid abuse, intoxication, and withdrawal symptoms:
Urgent safety: Possible opioid overdose
An opioid overdose is a medical emergency. Warning signs can include:- Very small or constricted pupils1
- Loss of consciousness1 or inability to wake the person
- Slow, shallow, or weak breathing2
- Choking or gurgling sounds
- Pale, blue, discolored, or unusually cold skin2
- A limp body2
Signs of heroin use
Heroin is an opioid drug made from morphine that is highly potent and addictive. Some of the behavioral signs of heroin use can include:
- Increased need for sleep
- Engaging in risky behaviors
- Wearing long sleeves or pants even in warm weather
- Slurred speech
- Bursts of hyperactivity
- Picking at skin
- Possession of injection paraphernalia, such as syringes and hypodermic needles
If you notice a combination of these signs, it could indicate that your loved one is abusing heroin.
Signs of fentanyl use
Fentanyl is a synthetic opioid. Because fentanyl is highly potent and may also be present in other illicit drugs, signs such as extreme drowsiness, slowed breathing, or an inability to wake someone should be taken seriously.
Signs of fentanyl use may include:
- Extreme drowsiness or repeatedly nodding off4
- Pinpoint pupils
- Slow or shallow breathing
- Confusion or difficulty concentrating4
Behavioral changes associated with fentanyl or other opioid use may include:
- Withdrawing from family, friends, or usual activities
- Neglecting responsibilities at home, work, or school
- Changes in mood, personality, or behavior
- Using opioids despite negative consequences
- Trying unsuccessfully to cut down or stop
Signs of cocaine use
Cocaine is a stimulant that increases activity in the central nervous system. Signs of cocaine abuse may include:
- Restless energy or an inability to sit still
- An inability to recall events
- Seeming exhausted even if they haven’t done any physical activity
- Acting confused or disoriented
- Being more talkative
- Needing less food or sleep
Signs of meth use
Methamphetamine is a stimulant, so signs of meth use can involve changes in the body, behavior, thinking, and mood. The changes a family member notices may depend on how frequently the person is using methamphetamine and other individual factors. Not everyone who uses methamphetamine will experience every symptom listed below. Physical changes may include:- Muscle twitching or tremors
- Rapid weight loss or loss of appetite5
- Skin sores
- Dilated pupils
- Significant changes in sleep
- Dental deterioration associated with chronic methamphetamine use
- Hyperactivity or unusually high energy5
- Secretive or withdrawn behavior
- Abandoning hobbies or activities once enjoyed
- Frequently borrowing or stealing money
- Declining work or school performance
- Risk-taking behavior
- Paranoia5
- Anxiety5
- Hallucinations
- Delusions
- Significant mood swings
- Psychosis
- Problems involving memory, attention, or decision-making5
Signs of prescription drug abuse
Prescription medications can be an important part of medical treatment when used as directed. However, some medications carry a risk of misuse, dependence, or substance use disorder, particularly when they are taken differently than prescribed.
Signs of prescription drug misuse may include:
- Taking a higher dose than prescribed
- Borrowing prescription medication from others
- Doctor shopping or visiting multiple doctors to obtain a new prescription
- Stealing or forging prescriptions
- Using medication faster than directed
- Stashing medication in various locations throughout the home
Signs of alcohol abuse
While alcohol is a legal substance for adults, it’s still addictive. Behavioral signs that indicate you or a loved one is misusing alcohol include:
- Decreased physical hygiene
- Abnormally passive or argumentative behaviors
- The smell of alcohol on their breath or clothing
- Slurred speech
- Coordination problems
- Changes in sleeping pattern
- Regularly appearing intoxicated
If you recognize a combination of these signs, then a person’s drinking habits could be harmful.
Signs of substance abuse in teens
It can be particularly challenging to recognize the signs of teenage drug use, as moodiness and irritability are already common for teens. If you’re concerned your teen may be misusing substances, pay attention to whether they are:
- Associating with different peers
- Missing class
- Skipping school
- Changing their eating and sleeping habits
Additionally, watch for sudden drops in academic performance or loss of interest in activities they once enjoyed.
Recognizing denial in addiction
Denial doesn’t necessarily mean that someone is intentionally lying or trying to manipulate the people around them. A person may genuinely have difficulty recognizing how much their substance use has changed or how seriously it is affecting their life.
Possible signs of denial in addiction include:
- Rationalizing substance use as necessary because of stress, pain, work, relationships, or another problem
- Comparing their use with someone else’s heavier use to make their own seem less concerning
- Dismissing concerns raised by family or friends
- Acknowledging some problems but believing their own situation is different
- Assuming the situation cannot be serious because they still work, attend school, care for family, or meet other responsibilities
Someone can continue functioning outwardly while still experiencing significant harm related to substance use. Holding a job or maintaining relationships doesn’t automatically rule out a substance use disorder.
This gap between outward functioning and what is happening privately can also make the question “Is my loved one addicted to drugs?” difficult for a family to answer. Learning more about understanding drug and alcohol addiction can provide additional context about why substance-related problems are not always easy to recognize.
When concerns continue, a professional assessment may provide more clarity. Learn more about how to get a substance use disorder evaluation.
What to do if you recognize these signs
One warning sign alone does not necessarily mean someone has a substance use disorder. When several behavioral or physical changes appear together, continue over time, or begin affecting daily life, recognizing the pattern early can provide an opportunity to seek professional guidance before concerns become more serious.
If you’re concerned about your own substance use or someone you love, Gulf Breeze Recovery offers substance abuse treatment programs using a holistic, non-12-step approach. The next step is to speak with the team about any of your concerns and available options.
Behavioral signs involve changes in actions, responsibilities, relationships, routines, or decision-making. Physical signs involve changes in appearance, coordination, sleep, energy, pupils, breathing, or other bodily symptoms. The two often occur together, and signs can vary by substance.
One sign alone usually does not confirm substance use. Look for several changes that persist or become more noticeable over time, such as withdrawal from family, declining performance at work or school, unusual financial problems, changes in appearance, or changes in sleep and behavior.
Signs of denial may include minimizing substance use, dismissing concerns from loved ones, comparing use with someone who uses more heavily, or believing the situation cannot be serious because the person is still meeting some responsibilities.
Yes. Someone may continue working, attending school, maintaining relationships, or caring for family while still experiencing significant problems related to substance use. Outward functioning does not rule out a substance use disorder.
A professional evaluation may be appropriate when several concerning changes occur together, continue over time, or begin affecting health, relationships, work, school, finances, or other areas of daily life.
