Signs and symptoms that an employee has a drug issue

How to identify if an employee is impaired in the workplace

Signs and symptoms that an employee has a drug issue

The holiday season has arrived, and many people will be celebrating with friends, family, and coworkers. Sometimes those festivities include alcohol as well as the use of both legal and unsanctioned illegal drugs. While substance use should always be responsible, sometimes it can spill over to other aspects of life, like the workplace. It is imperative health and safety professionals know how to recognize the signs and symptoms of a problem with drugs and alcohol.

The Canadian Centre for Occupational Health and Safety (CCOHS) says impairment on the job can be the difference between life and death. “Many aspects of the workplace require alertness, and accurate and quick reflexes. An impairment to these qualities can cause incidents and interfere with the accuracy and efficiency of work.”

The CCOHS outlines several situations where problematic substance use can lead to issues in the workplace:

  • any impact on a person's judgment, alertness, perception, motor coordination or emotional state that also impacts working safely or safety sensitive decisions
  • after-effects of substance use (hangover, withdrawal) affecting job performance
  • illness or injury
  • absenteeism, or reduced productivity
  • preoccupation with obtaining and using substances while at work, interfering with attention and concentration
  • illegal activities at work including selling illicit drugs to other employees,
  • psychological or stress-related effects due to substance use by a family member, friend or co-worker that affects another person's job performance.

The CCOHS says there is a spectrum of use that can range from casual to addiction or dependency. It says employers need to consider if a worker’s substance use poses a risk to their safety or the safety of others.  That all depends on what substances are being used or abused.  Here is a list of seven common substances and the observable effects they have on individuals.


This includes beer, wine, and spirits. While alcohol is legal across Canada, different workplaces have different rules regarding acceptable use.  Sometimes these can include limits on what a worker is allowed to drink while performing their duties, but many workplaces also have zero tolerance policies.  Signs and symptoms of excessive alcohol use include impaired judgement, slowed reflexes, impaired motor function, drowsiness, and coma. In extreme cases, alcohol poisoning can be fatal.

Sleep drugs

Benzodiazepines is a group of drugs commonly used to treat sleep disorders, anxiety, and seizures.  It can cause confusion, dizziness, drowsiness, memory loss, slurred speech, muscle weakness, imbalance.  Excessive use can also lead to delusions, hallucinations, sudden anxiety, restlessness, agitation, and sometimes feelings of euphoria. These should especially be avoided if a worker is operating heavy machinery or driving.


With recreational marijuana use legal across Canada, there are now pot shops popping up all over the place, and many different types of ingestion methods. You can drink it, eat it, or smoke it, and some workers may think it is acceptable to share in the workplace. Health and safety professionals should be aware of their company’s policies surrounding recreational marijuana use and remind workers about the policies that exist. Marijuana products can create a distorted sense of time, impair memory and coordination, and cause drowsiness. 


Opiates are among the most dangerous substances being abused, and has led to a nation wide crisis, often referred to as the opioid epidemic.  Opioids include legal drugs like morphine, codeine, fentanyl, and some mild sedatives.  But it also includes illegal drugs like heroine.  And while morphine, codeine and fentanyl are legal, there is an illegal trade of these drugs on the street.  Overdoses can be fatal, and these types of drugs can cause inattention, slow reflexes, imbalance, drowsiness, nausea, and depression.  Opioids are extremely addictive and should be treated with extreme caution if encountered in the workplace.


Hallucinogenic drugs make it almost impossible for an employee to function in a workplace setting and the signs and symptoms will be extremely obvious for managers.  These include drugs like LSD, PCP, mescaline, magic mushrooms, and salvia. These are psychoactive drugs that primarily trigger hallucinations (hence the name) but can also produce other effects such as sensory illusions, sweating, dizziness, sleeplessness, confusion, disorientation, psychosis, decreased coordination and weakness. 


While much less common than some of the other substances discussed in this article, inhalants are among the most easily accessible drugs because they are found in common household and workplace items.  Gasoline, paint, thinners, dry cleaning fluids, other solvents and hydrocarbons can all be inhaled to create intoxicating effects similar to alcohol.  Inhalants can cause dizziness, headache, muscle weakness, disorientation, inattentiveness, and depression.


Stimulants include several illegal drugs such as cocaine, crack cocaine, amphetamines, methamphetamines, and MDMA.  These also go by street names like crystal meth and ecstasy.  These can elevate mood and lead to overactivity, heightened confidence, panic, anxiety, paranoia, tremors, dizziness, and violent behaviour. Extended use can cause sleep problems, moodiness and depression.

Work places may wish to test their employees for drugs and alcohol, a controversial practice which has been upheld in the courts.  If health and safety professionals and workplace managers encounter drug use in the workplace it’s advised the worker be temporarily relieved of their duties and given appropriate access to substance abuse resources, including opportunities to attend rehabilitation programs and counselling.