When Canada legalized cannabis in October 2018, there were many concerns about its potential impacts. One of them involved cannabis-impaired driving.

Before legalization, police were already catching more drug-impaired drivers each year. So, people naturally worried that more stoned drivers would appear on the road after legalization.

To lower that risk, the federal government updated its driving laws. Impairment by alcohol or drugs separately was already illegal. In December 2018, Canada also banned impairment by combinations of alcohol adn drugs, or by## Police-reported impairment

my research analyzed the annual rates of impaired driving cases that police investigated between 2009 and 2023. The report covered four substance categories: alcohol, drugs, drugs-and-alcohol combined and unknown substances.

Note that “drugs” include cannabis but also other chemicals like opioids and amphetamines. Publicly available data unfortunately don’t name the drugs involved.

I first estimated the trends in alcohol and drug impairment up until 2018. I then calculated how much rates changed from 2019 onward.

I also checked several potential explanations for those changes. Those included the level of legalized cannabis sales and the share of adults consuming cannabis in each province. I also considered each province’s number of police trained in drug recognition and their degree of COVID-19 pandemic restrictions.

The data showed that during the 15-year study period, alcohol remained the most common impairment category. But its share of all cases dropped from 98% in 2009 to 95% in 2017 and to just 80% in 2023.

Up until 2018, the total impairment rate also fell each year.

More drinks and drugs

but in 2019, rates jumped substantially. As an inevitable result, police reported 31% more impairment cases during 2019-23 than the 2009-18 trend had projected.

The impairment increases varied between provinces. For example, there was no notable change in Québec and Saskatchewan.But rates doubled in British Columbia and Newfoundland.

Percentage-wise, the drugs category saw the most growth. It averaged 42% higher during 2019-23 than had been projected.

But alcohol impairment rose too. It averaged 17% above its previous trend.

And when counting drivers, alcohol’s growth was larger. The increase in drinking drivers caught by police was four times the increase in drugged drivers.

The new offenses for impairment by drugs and alcohol combined, or by unspecified substances, also contributed to the higher rate.

So,police clearly found more impaired drivers after 2018. But was that because more impaired drivers were on the road? Because police got better at catching them? Or both?

Constables,COVID and cannabis

Why some people are more sensitive to pain than others – and what can be done about it

Pain is a global experience,but why do some people feel it more intensely or for longer periods than others? The answer isn’t simple,but researchers are uncovering how genetics,life experiences,and even the brain itself contribute to individual differences in pain sensitivity.

What causes pain?

Pain isn’t just a signal that something is physically damaged. It’s a complex process involving the nervous system. When you injure yourself, specialized nerve cells called nociceptors detect the damage and send signals to the spinal cord and then to the brain. The brain interprets these signals as pain.

Though, pain isn’t just about the physical signal. Our brains also play a huge role in how we experience pain. Factors like emotions,past experiences,and expectations can all influence the intensity and duration of pain.

The role of genetics

Genes can influence how our nervous systems develop and function, impacting pain sensitivity. Variations in genes related to pain pathways, inflammation, and even mood regulation can make some people more vulnerable to chronic pain. For example, some people have genetic variations that make their nociceptors more sensitive, meaning they fire more easily in response to a stimulus.

However, genes aren’t destiny. They only account for a portion of the variation in pain sensitivity.

How life experiences shape pain

Early life experiences, especially adverse ones like trauma or chronic illness, can substantially alter the nervous system and increase pain sensitivity. These experiences can “rewire” the brain, making it more reactive to pain signals. This is often linked to changes in the brain regions involved in processing emotions and regulating stress.

Similarly, previous pain experiences can also shape future pain perception. If you’ve had a particularly painful experience in the past, your brain may become more sensitized, leading to increased pain with similar stimuli in the future. This is known as “pain memory.”

the brain’s influence

The brain isn’t just a passive receiver of pain signals; it actively modulates them. Areas of the brain like the prefrontal cortex and the amygdala play key roles in regulating pain.The prefrontal cortex helps us to cognitively reappraise pain – to change how we think about it – while the amygdala processes emotions associated with pain.

Differences in the structure and function of these brain regions can contribute to variations in pain sensitivity. Such as, people with chronic pain often show reduced activity in the prefrontal cortex, making it harder to regulate pain signals.

What can be done?

Understanding the factors that contribute to pain sensitivity opens up possibilities for more personalized pain management. Here are some approaches:

• Psychological therapies: Cognitive behavioral therapy (CBT) can help people change their thoughts and behaviors related to pain, reducing its impact. American Psychological Association – Cognitive Behavioral Therapy
• Mindfulness and meditation: These practices can help people become more aware of their pain without judgment, reducing emotional reactivity and improving coping skills.
• Exercise: Regular physical activity can release endorphins, which have natural pain-relieving effects, and improve overall physical function.
• Medications: While medications can be helpful for managing pain, they don’t address the underlying causes of pain sensitivity.
• Neuromodulation techniques: Techniques like transcranial magnetic stimulation (TMS) and spinal cord stimulation can directly modulate pain signals in the brain and spinal cord.

Ultimately, managing pain effectively requires a holistic approach that addresses the biological, psychological, and social factors that contribute to individual pain experiences. More research is needed to fully understand the complexities of pain sensitivity and develop even more targeted and effective treatments.