It's been over 20 years since California became the first state to legalize marijuana for medicinal purposes. Since then, 30 states, along with Washington D.C., have legalized medical marijuana. Despite being legal in a majority of the states, there are still many questions people have about the use of medical marijuana.

For those who want to know more, here are the answers to three frequently asked questions regarding medical marijuana.

1. What Conditions Can Medical Marijuana Legally Treat?

Just because marijuana is legal in many states, doesn't mean it can be used for every kind of medical condition. Each state has strict guidelines when it comes to what conditions medical marijuana can be used for. Most states allow patients with debilitating diseases and who have been admitted to hospice to use medical marijuana.

Patients who have chronic pain might also be approved for its use, especially in cases where other types of treatment have been ineffective. Some examples of conditions that medical marijuana is commonly used to treat include:

• HIV or AIDS
• Amyotrophic Lateral Sclerosis (ALS)
• Persistent muscle spasms
• Crohn's disease
• Post Traumatic Stress Disorder (PTSD)

Medical marijuana can also be used to treat pain associated with various types of cancer.

2. How Do Patients Get Medical Marijuana?

It's important to note that physicians cannot prescribe medical marijuana. All doctors who wish to recommend medical marijuana to their patients must register with the marijuana registry in their state. Patients who wish to use medical marijuana must also register.

In most states, when a patient registers, they will receive a Patient ID number. Once they have obtained written permission from a doctor who is also registered, they can obtain the legal amount of medical marijuana at an approved cannabis dispensary.

3. Are Medical Marijuana and CBD Oil the Same Thing?

Cannabidiol (CBD) is a cannabinoid produced from the seeds of hemp. While it is also used for medicinal purposes, it is not the same as medical marijuana. CBD oil contains only trace amounts of tetrahydrocannabinol (THC), the ingredient in marijuana that gives people a feeling of being high. Some CBD oil doesn't contain any THC at all.

CBD oil is exempt from federal law, which means people can purchase and consume CBD oil without a prescription from their physician. While many people use CBD oil to treat a variety of conditions, including anxiety, insomnia, and chronic pain, it has only been FDA approved to treat rare forms of epilepsy.