Education Information


What is medical marijuana?

Though marijuana, or cannabis, is commonly known as a recreational drug, it has been used as a medicine for thousands of years. Its recreational use is still illegal in all but a handful of U.S. states. Many states have legalized it for medical use, though the Food and Drug Administration (FDA) hasn’t approved it as a medicine.

The mind-altering ingredient in marijuana is THC, short for delta-9-tetrahydrocannabinol. The amount of THC in marijuana varies and has been steadily increasing over the past few decades. According to the National Institute on Drug Abuse (NIDA), the average THC content of confiscated samples was 3.7 percent in the 1990s. In 2013 it was 9.6 percent.

When THC enters the body it attaches to and stimulates cannabinoid receptors in the brain. The stimulation of these receptors affects the body in various ways. Among its effects are reduced pain and increased appetite.

Another chemical in marijuana that has beneficial health effects is cannabidiol (CBD). Unlike THC, this chemical isn’t psychoactive and doesn’t cause the intoxicating effects that THC does. According to NIDA, CBD can possibly be used to treat childhood epilepsy. It can also be turned into an oil for use as a healing salve. More research needs to be done into the effects of CBD.

In states where medical marijuana use is legal, a doctor must write a recommendation for the drug.

What does medical marijuana treat?

Researchers continue to study the medical benefits of marijuana. It may be effective in treating:

  • chronic pain, due of its effect on the central nervous system

  • nausea

  • muscle spasms, especially those associated with certain conditions, such as multiple sclerosis

New Jersey allows marijuana to be used to help treat these conditions:

  • chronic pain related to musculoskeletal disorders / chronic visceral pain

  • anxiety

  • migraines

  • Tourette's Syndrome

  • Amyotrophic lateral sclerosis

  • Multiple sclerosis

  • Terminal cancer

  • Muscular dystrophy

  • Inflammatory bowel disease, including Crohn’s disease

  • Terminal illness, if the physician has determined a prognosis of less than 12 months of life.

    The following conditions apply, if resistant to, or if the patient is intolerant to, conventional therapy:

  • Seizure disorder, including epilepsy

  • Intractable skeletal muscular spasticity

  • Glaucoma 

  • Post-Traumatic Stress Disorder

    The following conditions apply, if severe or chronic pain, severe nausea or vomiting,
    cachexia or wasting syndrome results from the condition or treatment thereof:

  • Positive status for human immunodeficiency virus (HIV)

  • Acquired immune deficiency syndrome

  • Cancer

Medical marijuana is used to relieve symptoms. It isn’t used to treat or cure diseases. Using it won’t change the outcome of a certain disease. But it can ease certain symptoms, make you feel better, and improve your quality of life.

Cannabis is most effective in treating chronic neuropathic pain. This is pain from nerve injury or disease. Because marijuana can make you hungry, it is also useful in treating conditions or side effects of diseases that cause a loss of appetite, such as AIDS.

What are the risks of medical marijuana?

One possible risk of cannabis use is addiction. The debate over whether cannabis is physically or psychologically addictive is ongoing. NIDA cites research that suggests 30 percent of marijuana users may become addicted, and people who smoke marijuana before the age of 18 are 4 to 7 times more likely to develop a marijuana use disorder than adults.

If you do become dependent on marijuana, you may have withdrawal symptoms if you stop using the drug. Withdrawal symptoms may include:

  • irritability

  • insomnia

  • mood difficulties

  • decreased appetite

  • physical discomfort

  • nausea

  • restlessness

Smoking tobacco leads to both COPD and lung cancer. Researchers are split on whether smoking marijuana can lead to these diseases as well. Marijuana smoke does contain some of the same elements as tobacco smoke. This raises concern for its effects on the lungs.

What are the side effects of medical marijuana?

Cognitive side effects of marijuana use include impaired:

  • short term memory

  • increased heart rate

  • low blood pressure

  • dizziness

  • sense of time

  • sensory perception

  • attention span

  • problem solving

  • speaking

  • reaction time

  • motor control

Other side effects of marijuana use are:

  • lowered blood sugar levels

  • drowsiness

  • increased bleeding

  • adverse interaction with other medications or herbs

People with mental or emotional disorders may have paranoia or hallucinations. It could also make their depression or mania worse. Your doctor will determine the specific dosage and frequency of medical marijuana use.

How to Use Medical Marijuana

Start Low and Go Slow

The basic principal for dosing medical marijuana is to start with a low dose and to go slow in taking more until the effect of the first dose is fully realized, because the effects of cannabis are not always immediately felt. Starting low and going slow allows patients to accommodate for the different experiences they may have.

Cannabis has a wide margin of safety and there is limited risk of overdose. However, caution is warranted until a patient fully understands the effect that the cannabis may have. Dosage varies greatly among patients, even when treating the same condition.

There are many factors that impact the effect, including:

  • Amount used (dosage)

  • Strain used and method of consumption

  • Environment/setting

  • Experience and history of cannabis use

  • Biochemistry

  • Mindset or mood

  • Nutrition or diet



Inhalation has the primary advantage of allowing a patient to adjust the dosage easily for maximum benefit because the onset of action is almost immediate. The medical marijuana is taken into the lungs and quickly absorbed through the capillaries into the bloodstream.

Forms of Inhalation

  • Hand or machine rolled cigarette (joint)

  • Pipe or water pipe (bong)

  • Vapor Inhalation

Length of Effect

Effects from inhaling cannabis products are felt within minutes and reach their peak in 10–30 minutes. Typical inhalers experience an effect that tapers off after approximately 2–4 hours, and lasts about 4–12 hours. As cannabis affects your cognitive abilities, you should not operate a motor vehicle, operate heavy machinery, or engage in any activity that requires full cognitive abilities until after the effect of the cannabis has completely dissipated, no less than 24 hours after use.

Smoking vs Vaporization

Smoking involves combusting the cannabis using an open flame. Vaporization steadily heats the cannabis to a temperature high enough to extract THC, CBD, and other cannabinoids into an inhalable mist, without burning.

Differences between smoking and vaporization:

  • With smoking, up to 40% of the available cannabinoids may be completely combusted or lost in side-stream smoke and thus are biologically unavailable.

  • A vaporizer steadily heats dried cannabis to a temperature that is high enough to extract THC, CBD, and other cannabinoids but too low to release the potentially harmful toxins that occur during combustion.

  • Vaporization is claimed to reduce some of the health risks associated with smoking.

  • There may be differing vaporization points for the individual cannabinoids and vaporized cannabis may have differing concentrations and ratios of cannabinoids compared with smoked cannabis.

Oral Administration

Many patients are more comfortable with oral administration of medical marijuana. Patients should consider, however, that absorption is slower when medical marijuana is taken orally, with lower, more delayed peak THC levels and reduced bioavailability of THC and CBD due to extensive metabolism in the digestive tract. While some studies have suggested that 3–5 times the quantity of medical marijuana is required to be taken orally to achieve the same effect as smoking, Harmony recommends each patient start low and goes slow.

Effects of Medical Marijuana

Short-Term Cognitive Effects

Patients should be aware that cannabis use causes short-term impairments in the following brain functions:

  • Memory

  • Sense of time

  • Sensory perception

  • Attention span

  • Problem solving

  • Verbal fluency

  • Reaction time

  • Psychomotor control

Cannabis users may “pull themselves together” to concentrate on simple tasks for brief periods of time. That said, performance impairments may be observed for at least one to two hours following cannabis use, and residual effects have been reported up to 24 hours depending on potency of the cannabis, the method of administration, and the tolerance of the user.

Long-Term Cognitive Effects

Consult the advice of your physician if you are a long-term user of medical cannabis and intend to stop using it, or if you are concerned about dependence on or addiction to cannabis. Your physician can help you manage any withdrawal effects that you may experience. Always seek the advice of your physician or other qualified healthcare provider before starting any new treatment or discontinuing an existing treatment with medical cannabis.

Talk with your healthcare provider about any questions you may have regarding your cannabis use. The information and materials provided to you by Harmony should not be used as a substitute for the care and knowledge that your physician can provide to you.

You need a doctor’s recommendation to use medical marijuana. Talk to your doctor if you feel it may help with your condition.