Health Risks

High time for hard facts: Medical marijuana

The current increase in medical usage of marijuana coupled with the trend toward decriminalisation of medical and recreational use could create the impression that the drug has well understood effects and benefits. In fact, scientific research on the topic is still at a very early stage. In studies, the active components of cannabis show pharmacological promise, but it will take time to determine their true value.


The history of medical use of marijuana, typically the dried leaves and flowering tops of the cannabis sativa plant or its derivatives, reaches back several millennia. It is known to have been used in Chinese medicine as early as 2727 B.C. It was introduced to Europe around 1840, and became established in the European and American medical communities in the decades that followed. More than 30 different preparations with cannabis as the active ingredient became available. Doctors recommended them for ailments as various as menstrual cramps, asthma, cough, insomnia, support of birth labour, migraine, throat infection and withdrawal from opium use.

But the popularity of marijuana as medicine did not last. Issues like quality control, difficulty in finding suitable delivery forms, unreliable effects and side effects were discouraging. Western medicine increasingly turned away from marijuana in the early 20th century.

The return of medical marijuana

The understanding of how marijuana functions has made considerable progress in recent decades. The components mainly responsible for the efficacy of the drug, termed cannabinoids, are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), which interact with the receptors of the cannabinoid receptor system. The human body produces its own natural version of cannabinoids, endocannabinoids. This explains why receptors are found throughout the body, but are especially prevalent in the brain. There are two main receptors, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2). 

CB1 receptors are primarily located in the brain and spinal cord in areas that affect pleasure, memory, pain, thinking, concentration and coordination. The main cannabinoid in marijuana, THC, acts on the CB1 receptors, inducing the psychoactive effects associated with recreational marijuana usage.

The second-most active cannabinoid in marijuana, CBD, activates CB2 receptors, which are located mainly on the cells of the immune system (e.g. spleen, white blood cells, tonsils). This activation produces no psychoactive effects and may actually mitigate some of the psychoactive effects of THC. 

This expanding knowledge regarding medical marijuana’s effects on the human body has prompted more research specifically targeting the two major active components. Today’s medical marijuana includes forms other than the most familiar smoked herbal marijuana, which has been linked to respiratory disease. The pharmaceuticals industry is investigating more effective ways to deliver the drug’s active components with more consistency and a better safety profile.

Promising results, but far from conclusive

In the United States, two cannabinoid drugs are approved and prescribed for nausea and vomiting due to chemotherapy and anorexia due to AIDS. Both are synthetic THC capsules taken orally. An oromucosal spray containing a combination of THC and CBD extracts is already approved in around 20 European countries and New Zealand, but also for limited indications only.

Yet the resurgence of marijuana as a prescription drug can be misleading. Current medical research has found only limited evidence to support cannabinoids for most other clinical conditions. With limited research on marijuana so far, valid scientific conclusions regarding its efficacy for medical conditions are hard to come by. More studies of the various components of the cannabinoid receptor system and a focus on the individual cannabinoids are clearly required to determine the value of medical marijuana for society.

Insurance implications

Medical marijuana can be relevant to various lines of business in a number of ways. In terms of life and disability insurance, its long-term mortality and morbidity risks remain unclear, but these are thought to include psychosis/psychiatric impairment, drug tolerance and drug dependence as well as risk for abuse as a substitute for narcotics or alcohol. A further potential risk is cognitive impairment and “drugged” driving leading to accidents. This last point poses a special challenge, as no reliable technology comparable to alcohol breath testing is yet available to determine driving under the influence of cannabis.

In any case, underwriters should consider the underlying disease and possible co-morbidities carefully. Around two-thirds of insurers already classify users of smoked herbal marijuana as smokers, according to a 2014 survey of the US market conducted by Munich Re. Although the effects of tobacco are far better understood and considerable research is required to determine the relative risk of marijuana smoking, there is evidence of harmful respiratory effects. Some clinical studies have suggested an association with lung cancer, but this has not been consistent. 

Regarding health insurance, the issue of qualifying conditions for prescription continues to evolve. Currently, medical marijuana is not a first-line therapy for any condition. There is considerable evidence that a significant proportion of medically dispensed marijuana is in fact destined for recreational use. As the drug gains acceptance and becomes widespread, there may be an increase in healthcare utilisation due to misuse (emergency rooms, poison control).

Property & casualty (P&C) lines may also be affected. The high value of the cannabis plants both before and after harvest as well as their legality should be considered. Growers, processors and dispensaries may require additional covers. A number of groups including healthcare professionals, medical marijuana producers and dispensers could face additional liability risks. These include general liability, product liability and recall and errors & omissions.

To sum up, medical marijuana is here to stay, and its applications can be expected to increase. More scientific research into its medical benefits and health risks is urgently needed. As the role of the drug evolves, the insurance industry will be required to respond flexibly.


Key facts

- Marijuana is not a first-line therapy for any medical condition
- Clinical research is lacking for most “approved” conditions
- Medical marijuana includes forms other than smoked herbal marijuana
- Potency and effects differ for smoked versus ingested marijuana
- Ongoing legalization of recreational marijuana complicates the picture
Further reading on Marijuana from the underwriting perspective