Medical marijuana: 18 states that permit pot

Got pot? If you're smoking marijuana for medical reasons, you could be breaking the law - or not. It depends on where you are.

In the U.S., 18 states plus the District of Columbia now have laws on the books permitting the use of medical marijuana. But the laws differ widely in whom they allow to smoke and how much pot they are allowed to possess.

Keep reading to see the details, as provided by Marijuana Policy Project and state resources.

Alaska

In Alaska, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, glaucoma, cachexia, severe pain, severe nausea, seizures, persistent muscle spasms and multiple sclerosis. A doctor's note is required.

Patients are allowed to possess one ounce of processed marijuana and cultivate six plants, only three of which can be mature plants.

Arizona

In Arizona, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, hepatitis C, amyotrophic lateral sclerosis, Crohn's disease, glaucoma, agitation related to Alzheimer's disease, severe and chronic pain, cachexia or wasting, severe nausea, seizures and persistent muscle spasms. A doctor's note is required.

Patients are allowed to possess two and one-half ounces of marijuana and 12 twelve plants to cultivate.

California

California is the only state to allow doctors to recommend medical marijuana for any condition.

Patients are allowed to possess at least eight ounces of processed marijuana and cultivate six mature plants or 12 twelve immature plants.

Colorado

In Colorado, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, glaucoma, severe pain, cachexia, severe nausea, seizures and persistent muscle spasms. A doctor's note is required.

Patients are allowed to possess up to two ounces of marijuana and can cultivate up to six plants, three of which may be mature.

Connecticut

Connecticut became the 17th state to legalize medical marijuana in June, 2012. Medical marijuana is approved in the state to treat the following conditions: "Cancer, glaucoma, HIV/AIDS, Parkinson's disease, multiple sclerosis, damage to the nervous tissue of the spinal cord with objective neurological indication of intractable spasticity, epilepsy, cachexia, wasting syndrome, Crohn's disease and posttraumatic stress disorder.

Adult patients may possess "an amount of usable marijuana reasonably necessary to ensure uninterrupted availability for a period of one month," as determined by the state's Department of Consumer Protection.

Delaware

In Delaware, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, decompensated cirrhosis, amyotrophic lateral sclerosis, agitation related to Alzheimer's disease, post-traumatic stress disorder. A doctor's note is required.

Patients are allowed to possess six ounces at once, but are not allowed to cultivate marijuana plants at home.

District of Columbia

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In Washington D.C., medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, glaucoma, severe and persistent muscle spasms and multiple sclerosis. A doctor's note is required.

Patients or caregivers are allowed to possess no more than two ounces in a 30-day period, which must be obtained from a dispensary.

Hawaii

In Hawaii, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, glaucoma, severe pain, cachexia or wasting, severe nausea, seizures, or severe and persistent muscle spasms. A doctor's note is required.

Patients or caregivers are allowed to collectively possess three ounces of processed marijuana and cultivate three mature plants and four immature plants.

Maine

In Maine, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, hepatitis C, amyotrophic lateral sclerosis, Crohn's diseases, nail patella, glaucoma, agitation related to Alzheimer's disease, intractable pain, cachexia or wasting, severe nausea, seizures and persistent muscle spasms. A doctor's note is required.

Patients are allowed to possess 2.5 ounces and can choose to cultivate up to six plants.

Massachusetts

Massachusetts became the 18th state to legalize medical marijuana after getting approved by voters during the November 2012 election.

In Massachusetts, doctors can now recommend medical marijuana for patients with certain conditions including cancer, glaucoma, HIV-positive status or AIDS, hepatitis C, Crohn's disease, Parkinson's disease, ALS, or multiple sclerosis, according to the Secretary of the Commonwealth of Massachusetts.

Patients need written certification from a doctor, which would allow them to have a 60-day supply of marijuana for personal medical use. Those who wish to cultivate their own marijuana must be unable to access treatment centers and would need a permit from the health department.

Michigan

In Michigan, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, hepatitis C, amyotrophic lateral sclerosis, Crohn's diseases, nail patella, glaucoma, agitation related to Alzheimer's disease, a severe and chronic pain, cachexia or wasting, severe nausea, seizures or severe and persistent muscle spasms. A doctor's note is required.

Patients are allowed to possess up to 2.5 ounces of marijuana.

Montana

In Montana, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, glaucoma, severe or chronic pain, cachexia or wasting, severe nausea, seizures and severe or persistent muscle spasms. A doctor's note is required.

Patients and caregivers are allowed to possess one ounce of marijuana and up to six plants.

Nevada

In Nevada, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, glaucoma, severe pain, cachexia, severe nausea, seizures and persistent muscle spasms. A doctor's note is required.

Patients and caregivers are allowed to possess one ounce of marijuana and cultivate three mature plants and four immature plants.

New Jersey

In New Jersey, medical marijuana is approved to treat the following conditions: amyotrophic lateral sclerosis, multiple sclerosis, muscular dystrophy, inflammatory bowel disease, terminal illness; if the condition is resistant to conventional treatments, seizure disorders; intractable skeletal muscular spasticity; glaucoma; severe pain, severe nausea, vomiting, or cachexia, HIV/AIDS or cancer. A doctor's note is required.

Patients are allowed to be dispensed two ounces of marijuana every 30 days.

New Mexico

In New Mexico, medical marijuana is approved to treat the following conditions: severe chronic pain, painful peripheral neuropathy, intractable nausea/vomiting, severe anorexia/cachexia, hepatitis C receiving antiviral treatment, Crohn's disease, post-traumatic stress disorder, amyotrophic lateral sclerosis, cancer, glaucoma, multiple sclerosis, spinal cord damage with intractable spasticity, epilepsy, and HIV/AIDS. A doctor's note is required.

Patients and caregivers are allowed to possess up to six ounces of marijuana.

Oregon

In Oregon, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, glaucoma, agitation related to Alzheimer's disease, cachexia, severe pain, severe nausea, seizures, or persistent muscle spasms, including those that are characteristic of multiple sclerosis. A doctor's note is required.

Patients and caregivers are allowed to possess 24 ounces of processed marijuana and cultivate six mature plants and 18 immature plants.

Rhode Island

In Rhode Island, medical marijuana is approved to treat the following conditions: cancer, HIV/AIDS, hepatitis C, glaucoma, agitation related to Alzheimer's disease, severe debilitating pain, cachexia or wasting syndrome, severe nausea, seizures and persistent muscle spasms. A doctor's note is required.

Patients are allowed to possess up to 2.5 ounces of marijuana and can cultivate up to 12 plants and 12 seedlings in an enclosed, locked area.

Vermont

In Vermont, medical marijuana is approved to treat the following conditions: cancer, multiple sclerosis, or HIV/AIDS or a chronic, debilitating severe pain, cachexia, severe nausea, or seizures. A doctor's note is required.

Patients are allowed to possess two ounces of processed marijuana and cultivate two mature plants and seven immature plants.

Washington

In Washington, medical marijuana is approved to treat the following conditions: cancer, HIV, multiple sclerosis, epilepsy, seizure and spasm disorders, intractable pain, glaucoma, Crohn's disease, Hepatitis C, and diseases causing nausea, vomiting, or appetite loss. A doctor's note is required.

Patients are allowed to possess a 60-day supply (presumed to be 24 ounces) of processed marijuana and 15 plants.