Cannabis and Mental Health: What the Evidence Actually Says
Cannabis eases anxiety for some people and triggers it in others. Here is what the research shows, who is most at risk, and how to lower the risk.
Quick answer
Smoking cannabis takes four steps. Grind the flower. Load it into a joint, pipe, or bong. Light the edge of the flower, not the flower itself. Pull smoke into your mouth, then into your lungs. Start with one small hit of flower at 15% THC or lower, then wait 10 minutes before the next hit. THC reaches the brain in seconds and peaks in 15 to 30 minutes.
What you need
- Cannabis flower, 0.5 g per joint or 0.1 g per pipe bowl
- Grinder or clean scissors
- Rolling papers (1 1/4 size, 78 mm) or a pipe, bong, or one-hitter
- Lighter or hemp wick
- Tray to catch loose flower
Step 1: Grind the flower
Break the buds into pieces the size of a pea. Turn the grinder two or three times. Stop when the flower looks like coarse salt. Fine powder burns hot and pulls through screens. Large chunks leave a hot center. Pick out stems and seeds.
Step 2: Pick a method
Joint
- Hold a paper between two fingers, glue strip up and facing you.
- Spread 0.5 g of ground flower along the center in a line.
- Roll the paper between your thumbs and index fingers, tuck the near edge over the flower, and tighten.
- Lick the glue strip, seal the paper, and twist the ends.
Pipe
Pack 0.1 g into the bowl. Leave air space above the flower. Draw through the pipe before you light it to check the pull. A clogged pipe gives a harsh hit.
Bong
Fill the base with water to the level of the downstem slot. Pack a bowl of 0.1 g to 0.2 g. Light the edge, pull the bowl, then clear the chamber. Water cools the smoke. Water does not filter out THC.
One-hitter
A one-hitter holds 0.05 g to 0.1 g. This is the smallest dose of any smoking method. Use it to test how your body responds.
Vape
Dry herb vaporizers heat flower to 350 F to 430 F (177 C to 221 C). Heat releases THC vapor without burning the plant. Buy cartridges from licensed shops only. Counterfeit cartridges have caused lung injury.
Step 3: Light and inhale
Hold the flame near the edge of the flower. Keep the flame off the bud. Draw smoke into your mouth first, then pull air on top of it into your lungs. Hold 2 to 5 seconds. Exhale. Take one hit at a time.
Step 4: Wait and dose
Smoking hits fast. Use one hit, then wait 10 minutes before the next. THC in flower is stronger now than it was in the 1990s. A bud labeled 25% THC gives more effect per hit than 10% flower. New users should start at 15% THC or lower. CBD does not cancel THC. It can lower anxiety and a racing heart.
Common mistakes
- Packing too much flower in a bowl. The top burns to black ash.
- Putting the lighter flame on the bud. It burns terpenes and ruins the taste.
- Holding smoke for 20 seconds. THC absorbs in 2 to 3 seconds. Longer holds add carbon monoxide, not THC.
- Driving after use. THC impairs reaction time and lane control for hours.
Risks
Cannabis smoke holds tar, carbon monoxide, and other chemicals. Smoke irritates the throat and airways. Daily use can cause coughing and bronchitis. Heavy use is linked to memory problems, attention problems, and cannabis use disorder. People with a history of psychosis, heart problems, or pregnancy should not use cannabis. Check your state law. Cannabis is legal for adults in many US states and illegal under federal law.
Storage
Keep flower in a sealed glass jar at 60 F to 70 F. Keep the jar out of light and heat. Dry flower loses potency in months. Label the jar with the THC content and the date you opened it.