Cannabis use may have a wide range of effects, both physical and mental. Every person can experience different effects with variation in intensity and duration.  

How cannabis affects a person depends on several factors:

• Amount taken
• Frequency of use
• Use with other substances (e.g., alcohol or other drugs), which could increase risk of harm
• Mode of use (e.g., consuming edibles or products with high THC concentration can have delayed or unpredictable effects and increases the risk of overdose or poisoning)
• Previous experience with cannabis or other drugs
• Biology (e.g., genes, DNA)
• Sex (e.g., women or people assigned female at birth may experience more dizziness after using cannabis compared to men or people assigned male at birth)

Physical Effects:

• Breathing problems. 
• Cannabis smoke irritates the lungs, and people who smoke cannabis frequently can have the same breathing problems as those who smoke tobacco.
• Increased heart rate. 
• Cannabis raises heart rate for up to 3 hours after smoking. This effect may increase the chance of heart attack. Older people and those with heart problems may be at higher risk.
• Problems with child development during and after pregnancy. 
• Intense nausea and vomiting. 

Mental Effects:

• Temporary hallucinations
• Temporary paranoia
• Worsening symptoms in patients with schizophrenia—a severe mental disorder with symptoms such as hallucinations, paranoia, and disorganized thinking.

Linked to other mental health problems, such as depression, anxiety, and suicidal thoughts among teens. However, study findings have been mixed.

Sources: Centers for Disease Control (CDC), National Institute on Drug Abuse

Short-term effects:
When a person smokes cannabis, THC quickly passes from the lungs into the bloodstream. The blood carries the chemical to the brain and other organs throughout the body. The body absorbs THC more slowly when the person eats or drinks it. 

Cannabis over activates parts of the brain that contain the highest number of these receptors. This causes the "high" that people feel. 

Other effects include:

• altered senses (for example, seeing brighter colors)
• altered sense of time
• changes in mood
• impaired body movement
• difficulty with thinking and problem-solving
• impaired memory
• hallucinations (when taken in high doses)
• delusions (when taken in high doses)
• psychosis (risk is highest with regular use of high potency marijuana)

Sources: National Institute on Drug Abuse

Longer-term effects 
Recent studies have shown that Cannabis affects brain development. When people begin using cannabis as teenagers, the drug may impair thinking, memory, learning functions, and affect how the brain builds connections between the areas necessary for these functions. Researchers are still studying how long these effects last and whether some changes may be permanent.

Sources: National Institute on Drug Abuse