How to Tell If Your Child Has Been Using Marijuana

Teen boy's hands putting marijuana in a baggie
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Naturally, most parents would prefer not to find out that their children are smoking marijuana while they are young. Even if you have a tolerant attitude toward marijuana or perhaps smoke it—or used to smoke it—yourself, you probably would not want your young children to use it due to the damage it can do to their young, developing brains.

Or, you may be like many parents and think that your child will not get involved with drugs or alcohol, because you have discussed the dangers with them, and besides, smoking weed is something that older children do, not your child.

Earlier Marijuana Use

One problem is children today are beginning to smoke marijuana very early in life. National surveys may indicate that the average age that children first smoke weed is 16, but that means many of them started much earlier for the average to be age 16.

In fact, one survey of children in treatment for substance abuse found that 14% of them first smoked marijuana before age 13.

Increased Marijuana Availability

Another problem is availability. Research has found that availability plays a large role in youngsters becoming involved with substance abuse whether it is alcohol, inhalants, prescription drugs, or marijuana.

Make no mistake about it, marijuana is becoming more and more available to young children, even in elementary and middle school. In response to surveys, a growing percentage of teens report that they know someone who sells drugs or know where they can buy drugs. In fact, some teens report they can get marijuana easier than they can alcohol.

Legalization Has Changed Attitudes

The growth of the marijuana legalization movement in the United States—for both medical and recreational use—has had an effect on how children perceive the use of marijuana. Fewer teens report seeing it as harmful or dangerous.

And finally, if you are a parent who does smoke marijuana, or even if you merely express approval of the use of weed around your children, they are much more likely to smoke it themselves compared with children whose parents disapprove of the drug.

Given all of these factors, you might want to rethink whether or not your child might be involved in marijuana use, especially if they have shown any of the signs outlined below.

Risks Associated With Early Marijuana Use

It is also important to be aware of the potential long-term damage that marijuana use can cause in young people. Research suggests that marijuana use can harm developing brains and lead to problems with thinking, problem-solving, attention, and coordination. Marijuana use is also linked to an increased risk for mental illness. Evidence also suggests that while the brain experiences recovery once marijuana use stops, the damage is lasting.

How to Spot Marijuana Use

 If someone is actually high on marijuana, there may be some visible signs that they are under the influence:

  • They may seem unsteady on their feet or appear dizzy.
  • They could have bloodshot eyes.
  • They might laugh inappropriately or seem silly for no reason.
  • They may have difficulty remembering something that just happened.
  • As the effects wear off, they may become sleepy.

Evidence of Smoking Behavior

Even if they are not visibly high, there are some signs you can look for that linger after they have been smoking:

  • The odor will linger and cling to their clothes
  • Drug paraphernalia such as rolling papers or pipes
  • Sudden uncharacteristic use of eye drops
  • The use of incense or room deodorizers
  • Pro-drug slogans on t-shirts or posters
  • Evidence of smoking, such as lighters, ashes

Sudden Behavioral Changes

Although these behavioral changes could be related to other typical teenage issues, they also could indicate marijuana use:

  • Tiredness
  • Hostility or mood swings
  • Social withdrawal
  • Depression
  • Declining attention to hygiene, grooming
  • Deteriorating relationships

Changes in Interests

These signs could also indicate other teenage-related problems, they also could be prompted by the use of marijuana:

  • A change in friends or peer group
  • Declining grades in school
  • Increased absenteeism or truancy
  • Changes in eating habits
  • A change in sleep patterns
  • Loss of interest in sports or other activities
  • Behavioral problems at school
  • Brushes with the law

What to Do If You Suspect Marijuana Use

If you suspect that your child has been using marijuana, you may want to just sit down and talk to them about it. If your child is using marijuana, chances are he or she will deny it and blame any evidence you found on someone else.

But, carefully watch their reaction to your conversation with them. If they over-react, that too could be an indication of their involvement with marijuana or other drugs.

How about drug testing your child? There are home drug tests available that parents can use to test their children, but be aware that there are some drawbacks when parents decide to test their kids.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

4 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. U.S. Department of Health & Human Services. Substance Abuse and Mental Health Services Administration. Talking With Your Child About Marijuana: Keeping Your Kids Safe.

  2. Freisthler B, Gruenewald PJ. Examining the relationship between the physical availability of medical marijuana and marijuana use across fifty California cities. Drug Alcohol Depend. 2014;143:244-50. doi:10.1016/j.drugalcdep.2014.07.036

  3. Bailey JA, Hill KG, Guttmannova K, et al. Associations Between Parental and Grandparental Marijuana Use and Child Substance Use Norms in a Prospective, Three-Generation Study. J Adolesc Health. 2016;59(3):262-268. doi:10.1016/j.jadohealth.2016.04.010

  4. Hurd YL, Manzoni OJ, Pletnikov MV, Lee FS, Bhattacharyya S, Melis M. Cannabis and the developing brain: insights into its long-lasting effectsJ Neurosci. 2019;39(42):8250-8258. doi:10.1523/JNEUROSCI.1165-19.2019

Additional Reading

By Buddy T
Buddy T is an anonymous writer and founding member of the Online Al-Anon Outreach Committee with decades of experience writing about alcoholism.