Signs of Drug Abuse Series 1 – Marijuana

Welcome to the “Signs of Drug Abuse” series. Over the next few weeks, we’ll be taking a closer look at some different drugs and the effects they have when used. In this article, we take a look at marijuana.

What would you do if you noticed a colleague acting strangely? If you’re concerned about the behaviour of someone you work with, it’s important you know when to act, and how to how to handle the situation sensitively. Here, we look at the different symptoms exhibited by a marijuana user, and what to do if you think someone is under the influence at work.



Marijuana has a pungent scent with many describing it as herbal or tea-like. It sticks to hair and clothing and is difficult to mask. If a colleague has smoked marijuana before or during their shift, you may notice they smell different or are wearing heavy perfumes or deodorant to cover it up.


Increased appetite.

One of the common side effects to marijuana use is getting “the munchies”, or a craving for junk food. If a colleague shows signs of binge eating or snacking more than usual, it could be more than just a change in diet.


Drug paraphernalia.

Marijuana users may bring drug materials to work with them. They may have suspicious-looking pre-rolled “cigarettes” in their possession, or could be carrying a grinder (used to break marijuana into smaller pieces). If you see materials you believe are being used for drugs, it’s important to tell someone.



Marijuana can cause users to have a lack of energy and motivation. A colleague may show a loss on interest in things that used to be significant to them, or be sleepy at work.


Sudden financial problems.

A drug habit can be expensive, so sudden unexplained financial issues could be an indicator of a more worrying problem. Legal issues could be another indicator, as they could be facing problems for transporting the substance or being caught with it elsewhere.


Changes in mood.

Whether they’re acting overly relaxed in stressful situations, or becoming paranoid and unfocused during moments of calm, a colleague acting out of character could be under the influence.


Physical signs.

Marijuana can make eyes appear bloodshot and unfocused. It can also cause a dry mouth, a mucus cough, rapid heartbeat, and a much slower reaction time.


Marijuana is the most commonly used illicit substance. While not as addictive as tobacco, studies show 10% of people who do smoke marijuana show signs of addiction after a period of time.

If you notice the above signs and are worried about a colleague, it’s important to speak up not only for their safety but for other colleagues safety, too. We recommend speaking in confidence to your HR department or manager for advice. It’s important to be as sensitive and professional as possible.


If you’re unsure what action to take, you can give SureScreen a call for private, confidential advice on 01332 365318.