How Does Cannabis Change Your Personality?

Posted on February 24, 2026

How Does Cannabis Change Your Personality?

Cannabis, or weed, is one of the most widely used psychoactive substances across the world, but its effects go beyond feeling “high”.

Many people also wonder whether long-term cannabis use can change their mood, behaviour, or even parts of their personality.

It is important to understand how cannabis interacts with the brain and your personality when thinking about overall mental health, relationships, and life goals.

This article explains more about how cannabis can alter personality, cognition and emotional functioning.

The Affect of Cannabis on the Brain

Cannabis contains several active compounds, including THC (tetrahydrocannabinol) which binds to the endocannabinoid system in the brain. This system is involved in regulating memory, emotion, decision-making and stress responses. [1]

Immediate and Short-Term Effects of Cannabis

Cannabis impacts the brain immediately, causing:

Temporarily impaired memory, attention and coordination
Mood and changes to perception, such as relaxation or paranoia

While these short-term effects don’t necessarily mean a core personality change, but cannabis can briefly alter how someone interacts with others.

Can Cannabis Influence Your Personality in the Long-Term?

There is not a simple answer to whether cannabis causes lasting personality, and it is still being studied.

However, there is scientific evidence suggesting that there can be long-term behavioural and cognitive impacts, especially with heavy or frequent use. Long-term effects are particularly noticeable if use starts at a younger age.

Impacts on brain development

Cannabis is known to affect the brain areas responsible for memory, attention, learning, decision-making and emotional regulation.

These effects are important to remember in children and young adults, since the brain continues developing until around age 25.

If someone under 25 frequently uses cannabis, they may have challenges with memory and learning that persist beyond the use time.

Research also finds structural and functional differences in the brains of regular cannabis users, but it is not certain if these changes cause personality shifts. [2]

Impacts on behaviour and psychology

Some studies have reported a link between cannabis use and the following:

Changes in motivation – heavy use of cannabis has been associated with a reduced drive or interest in pursuing long-term goals. [3]
An altered sense of psychological wellbeing – frequent users in young adulthood showed increases in anxiety, depression and reduced overall wellbeing. [4]
A risk of psychosis-like experiences – this is especially with high-THC cannabis use during adolescence. [5]

It’s important to remember, though, that this link does not always mean cause, with other factors like genetics, environment and mental health history also playing a role. [6]

Signs Cannabis Might be Impacting Your Behaviour

When cannabis use is starting to influence your personality or daily life, you may notice changes such as:

Lower motivation
Feeling more irritated than usual
Memory issues
Less social engagement

These changes may happen more for people who frequently or heavily use cannabis.

Getting in touch with a healthcare professional can help you to see the difference between substance-related effects and underlying mental health problems.

The Gaps in Research in Cannabis Use

There is no absolute evidence that cannabis rewires someone’s inherent personality permanently in everyone who uses it.

Many studies, as shown above, show a link between cannabis use and cognitive or behavioural differences, but disentangling cause and effect can be more challenging.

However, a large amount of evidence supports the idea that regular, heavy use, especially if you have started in early life, means a greater risk of lasting impacts on mood and cognitive function.

If you’re concerned about your cannabis use and worry if it’s changing your personality, it’s best to explore your options of support.

Rehab Treatment for Cannabis

If you think you need further help for your cannabis use, you may want to consider a rehab or detox facility where you will have full access to treatments and support.

You will receive a personalised rehabilitation programme, including help to prevent future relapses and continued use.

The recommended treatment time is 28 days, which allows time for individual counselling, group therapy, cognitive behavioural therapy, mindfulness activities, and other holistic programmes.

Call us today at 0800 088 66 86 for free, no-obligation guidance, and take the first step towards recovery.