Cannabis is used by millions of people for different reasons—some for fun, others for health. But how does it actually affect your body and brain? Like any substance, cannabis has both short-term and long-term effects. Some are helpful, and others depend on how much you use and how often.
Let’s break down the known facts about how cannabis works and what it can do to you.
Short-Term Effects of Cannabis
When you use cannabis—especially products with THC—you can feel the effects within minutes (if smoked or vaped) or up to two hours later (if eaten).
Common short-term effects include:
- Feeling relaxed or calm
- A sense of euphoria or being “high”
- Increased appetite (“the munchies”)
- Dry mouth and red eyes
- Slower reaction time
- Changes in how you see, hear, or feel things
- Short-term memory problems
- Trouble focusing or making decisions
These effects are usually temporary and go away within a few hours. How strong they feel depends on the dose, the type of cannabis, and your own body.
Medical Benefits Being Studied
Cannabis has shown promise in helping with many medical conditions. While more research is still needed, many people use it for relief from:
- Chronic pain
- Nausea and vomiting from cancer treatment
- Muscle spasms from conditions like MS
- Seizures, especially in certain forms of epilepsy
- Anxiety or PTSD symptoms
- Sleep problems like insomnia
- Appetite loss (especially in people with HIV or cancer)
In some cases, doctors prescribe cannabis-based medicine. For example, the FDA has approved Epidiolex (a CBD medication) for epilepsy, and dronabinol (a THC pill) for nausea and weight loss.
CBD vs. THC Effects
The two main cannabis compounds—CBD and THC—affect the body differently:
- THC makes you feel high and affects the brain
- CBD does not make you high and is often used to reduce inflammation, anxiety, or seizures
People looking for health benefits without feeling “high” often choose CBD products, especially those made from hemp.
Long-Term Effects of Cannabis
Regular cannabis use over time may cause changes in how your brain works, especially if you start young or use high amounts.
Possible long-term effects include:
- Memory and learning problems
- Lower motivation or interest in tasks
- Higher risk of lung issues (if smoking often)
- Increased anxiety or mood changes
- Possible risk of addiction in some users
- Trouble sleeping without cannabis
The risk for these problems is higher in people who start using cannabis heavily at a young age or those who use high-THC products often.
Mental Health Impacts
Cannabis can affect mental health in both helpful and harmful ways:
May help with:
- PTSD
- General anxiety
- Depression (in low doses)
May worsen or trigger:
- Panic attacks (especially in new users or with high THC)
- Paranoia
- Psychosis in people at risk (especially if there’s a family history of mental illness)
Everyone reacts differently, so it’s important to listen to your body and mind—and to talk to a doctor if you have mental health concerns.
Is Cannabis Addictive?
Cannabis can lead to a condition called Cannabis Use Disorder in some people. This means someone has a hard time stopping even when it’s affecting their life.
Signs of cannabis dependence may include:
- Needing more to feel the same effect
- Feeling anxious or irritable when not using
- Using cannabis to cope with stress
- Struggling to cut back or quit
About 1 in 10 cannabis users may develop a dependence. That number goes up to 1 in 6 for people who start using before age 18.
Use It Smart, Use It Safe
Cannabis can be helpful or harmful, depending on how it’s used. If you’re going to use cannabis:
- Start with small amounts
- Choose products with lower THC
- Avoid mixing with alcohol or other drugs
- Take breaks from using it regularly
- Don’t drive or operate machines while high
Cannabis affects everyone differently. Understanding how it works helps you enjoy it safely and get the benefits you’re looking for.
