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Let’s Talk Cannabis

General information
Let’s Talk Cannabis

Under California law, adults 21 or older can now use, carry, and grow cannabis, also known as marijuana, weed, pot or bud. In a recent survey of San Mateo County residents, 58 percent of respondents reported currently or previously using cannabis. You probably have a lot of questions about cannabis. We’re here to answer some of those questions, but it’s also a good idea to talk to your doctor.

Using marijuana daily can lead to changes in your brain, especially for young people, whose memory, learning and attention can be harmed. The marijuana available today has much higher tetrahydrocannabinol (THC) concentrations than cannabis from years ago (20 to 30 percent, compared to 2 to 5 percent in the ‘90s).

You probably have lots of questions about the effects of marijuana. We can answer some of those questions, but it’s also a good idea to talk to your doctor.

Responsible Use

Like any drug, repeated cannabis use can lead to substance use issues. Research shows that about 9 percent, or 1 in 11 users will become addicted. This rate increases to 17 percent (1 in 6 people), who start in their teens, and goes up to 25 to 50 percent among daily users. Negative effects on attention, memory and learning can last for days and sometimes weeks – especially among regular users.

If you are going to use cannabis, be smart.

While a fatal overdose is unlikely, too much cannabis can lead to unwanted effects. Symptoms of using too much can include increased heart rate, increased blood pressure, hallucinations or delusions, severe nausea and vomiting, confusion, anxiety, panic or paranoia.

If you or someone you know has any of the symptoms above, call the Poison Control Hotline at 1-800-222-1222. If the symptoms are severe, call 911 or go to an emergency room.   

Driving under the influence of cannabis is illegal and unsafe. It increases your risk of getting into a car crash and you can receive a DUI if operating a car, boat or other vehicle while under the influence of cannabis.

If you are pregnant, thinking about becoming pregnant or breastfeeding, you should not use cannabis. Tetrahydrocannabinol (commonly referred to as THC) passes to the fetus through the placenta and to infants through breast milk.  Check out this fact sheet or find out about the risks here.

Keep in mind that consuming cannabis in different ways can have different effects. If you smoke or vape cannabis, the effects may be immediate. Edibles can take anywhere from 30 minutes to two hours to kick in. Eating too much, too fast can increase risk of poisoning.

Check out this fact sheet for more information on using cannabis responsibly.

Youth/Young Adults

As a young person, you have an incredible capacity to learn, grow and experience new things. Your brain is actually still developing every single day, and will continue to do so up to the age of 25, so it’s important to protect it. Using cannabis can lead to physical changes in your brain that can harm your memory, learning and attention.

Just like cigarettes, smoking cannabis can harm your lungs. Using cannabis also increases your risk of anxiety, depression, suicide, schizophrenia and substance use issues.

Legal Consequences

If you are under 21 and caught in possession of cannabis you will be required to complete drug education or counseling and community service, and depending on your location and prior offenses, you can be fined and even receive jail time. Driving under the influence of cannabis at any age is illegal and unsafe.

Check out this fact sheet for more information.

Parents and Mentors

A recent survey of San Mateo County residents, 54% percent of respondents reported being very concerned about youth marijuana use in their communities. It’s up to all of us to help prevent and delay marijuana use among our youth.

Parents and mentors in particular have a huge impact on whether or not youth use marijuana. Pre-teens, teens and youth in their early 20s often seek out new experiences and engage in risky behaviors, such as using cannabis. You can help prevent underage use by starting an honest, open conversation about cannabis use and its potential consequences.

Provide guidance about the risks of using cannabis, and set shared guidelines and expectations for healthy behaviors. Be aware that your own attitudes and behaviors can impact the way youth in your life think about cannabis.

Cannabis affects children more strongly than adults, placing them at a higher risk of cannabis poisoning, especially from edibles. Be sure to keep all cannabis products in a locked area that children cannot see or reach.

For more information, check out this fact sheet and stop by our next parent education workshop.

Additional Resources

San Mateo County is developing a youth marijuana education campaign. Read about it here, and stop by our next parent education workshop.

For additional information about cannabis regulations, health and research, check out the California Department of Public Health’s resources.

To find more information on San Mateo County regulations and the County Cannabis Cultivation Ordinance, visit:

You can find information on the county’s Alcohol and Other Drug Services here