Parents can learn the signs and symptoms of substance use in teens.

Substance use in teens is a common issue that can have grave consequences. Often parents feel as if they have no power when it comes to their teens’ substance abuse, and may not even know that it is happening at all. As prevalent as substance abuse is, it’s important for parents to know the signs of drug use in teens.

Teens who are under the influence often give clues without even realizing it. Finding out that your teen is on drugs is one of the most frightening realities a parent can face and difficult for any mother or father to confront – but learning the signs and symptoms of intoxication could end up saving a life. 

Dilated Pupils

Pupil dilation with drug use is a common sign for certain types of substances. Dilated pupils are easy to detect by simply looking at your teen’s eyes to determine whether their pupils are enlarged beyond what they normally would be. Substances that can cause dilated pupils include marijuana, amphetamines, cocaine, MDMA, LSD, ecstasy and others. 

The pupils respond differently when the brain is under the influence of these substances. The muscles that control dilation are affected by drug use and this is one indicator that your teen may have used.

Red Eyes

Along with dilated pupils, if your teen is smoking pot, you may also notice that they have red eyes. Your teen may also have a difficult time keeping their eyes open. Marijuana use in teens is a common issue and it is wise to have an awareness of the signs of use. Red or bloodshot eyes are a common sign of marijuana use and may be a positive indicator of drug use in your teen.

Changes in Speech

If your teen is using alcohol, you may be able to discover their use as a result of speech changes. Even if your teen is trying to hide their substance use, often changes in speech patterns are an indicator of drug or alcohol abuse. Slurred speech or pauses between words may indicate that your teen is not functioning at their usual cognitive levels, which may mean that they have been using alcohol. Teens using cocaine will likely have faster speech patterns than usual. Cocaine is a stimulant, causing it to increase the heart rate, thought processes and speech patterns. 


Teen prescription drug use is steadily on the rise. Parents can increase their awareness of the signs and symptoms of opiate and other prescription drug abuse and intervene to help keep them safe. There are certain drugs that make you sweat excessively. While there are many non-abuseable medications that can cause sweating, if your teen is exhibiting hyperhidrosis, it may be a sign of opioid abuse. Drugs such as Vicodin, methadone and Fentanyl are commonly associated with sweating, as well as Oxycontin. These medications are dangerous and easy to overdose on, which makes the identification of symptoms even more important. 


Observe your teen’s neurological signs and symptoms. Teen drug use can sometimes be detected by their external neurological behaviors such as fine and gross motor movement. If your teen is on crystal meth, you may notice that they are jittery or demonstrate a tremor. This is a difficult symptom to hide and may provide clues of substance use in your teen. Amphetamine abuse is commonly associated with involuntary limb movement and observable jitters. 

What If I Find Out My Child is On Drugs?

Concerned parents may wonder what to do when their child is on drugs. If you suspect your teen is abusing drugs, it is important to provide an intervention as soon as possible to protect them from further physical and social risks associated with addiction. Help is available for teens who need drug rehab. Parents and teens don’t have to face this alone, reach out to The Recovery Village and learn about treatment options today.

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Editor – Daron Christopher
Daron Christopher is an experienced speechwriter, copywriter and communications consultant based in Washington, DC. Read more
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Medically Reviewed By – Paula Holmes, LCSW
Paula Holmes is a licensed clinical social worker, psychotherapist and freelance writer who lives and works in midcoast Maine. She received her master's degree in Social Work in 2008 from the University of Maine. Read more
Sources “Signs and Symptom of Drug Use.” Accessed August 16, 2019.

Shahid, Ali, M.D., Mouton, Charles P. M.D., Jabeen, Shagufta, M.D. et al. “Early Detection of Illicit Drug Use in Teenagers.” National Institutes of Health. December 2011. Accessed August 16, 2019.

National Institute on Drug Abuse. “Signs of Cocaine Use.” Accessed August 16, 2019.

Simpson, Jamie. “Drugs That Would Cause Excessive Sweating.” Accessed August 16, 2019.

Rusyniak, Daniel E. M.D. “Neurologic manifestations of chronic […]thamphetamine abuse.” National Institute of Health. August 2011. Accessed August 16, 2019.


Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.