How can I tell if someone is using drugs?

signs of drug use

This resource has undergone expert review.





How can I tell if someone is using drugs?

There are some signs and behaviours that may raise concern that your child is using drugs, however many of these signs are also common among teenagers so it's important not to jump to conclusions.

Some signs of drug use may include: 

  • Withdrawal from friends and family
  • Change in friendships or problems with friends
  • A drop in grades or attendance at school
  • Signs of sadness, depression, agitation or hostility
  • An increase in borrowing money
  • Evidence of drug paraphernalia or missing prescription drugs.

Some signs that someone may be under the influence of a drug include:

  • Enlarged pupils, bloodshot or glassy eyes
  • Increased energy and confidence
  • Loss of inhibitions
  • Loss of coordination
  • Aggressive behaviour
  • Trembling, twitches
  • Paranoia (being extremely suspicious)
  • Hallucinations (hearing or seeing things that aren’t really there)
  • Nausea and vomiting
  • Complaints of stomach cramps, blurred vision, headaches or dizziness
  • Exhaustion, fatigue or insomnia (being unable to sleep)
  • Irritability and moodiness
  • Changes to eating patterns such as eating less or more
  • Anxiety symptoms such as panic attacks, dizziness, sweating, dry mouth, muscle aches and headaches.

Remember that drugs can affect different people in different ways. For more information about different drugs and their specific effects, see our drug factsheets page.

If you are worried that your child may be using alcohol or other drugs, Positive Choices provides tips to help you start a conversation, information about the warning signs that someone might be dependent on a drug and where to get help and advice.

Evidence Base

This factsheet was developed following expert review at the Matilda Centre for Research in Mental Health and Substance Use at the University of Sydney and the National Drug & Alcohol Research Centre at the University of New South Wales.

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