Medical marijuana
Although cannabis extracts were marketed by major pharmaceutical companies and widely used by consumers for various ailments during the late 1800s, medicinal cannabis use in the United States declined significantly during the early 20th century. In 1937, the Marihuana Tax Act was passed, effectively putting a stop to physicians prescribing cannabis for medical purposes. The FDA currently classifies cannabis as a Schedule I drug (eg, high abuse potential, no currently accepted medical use, lack of safety data) and the use of cannabis and its prescription by physicians are prohibited under federal law.
However, in recognition of the potential medical benefits of cannabis, 16 states have legalized medicinal use (“medical marijuana”) over the past several years. Laws and regulations governing medical marijuana vary from state to state. For example, in California, adults who obtain a recommendation from a physician and register for a Medical Marijuana Identification Card can legally purchase cannabis from a state-recognized dispensary and use it in a non-public setting. The physician’s “recommendation” (not a prescription) is based upon the determination that “the person’s health would benefit from the use of marijuana in the treatment of cancer, anorexia, AIDS, chronic pain, spasticity, glaucoma, arthritis, migraine, or any other illness for which marijuana provides relief”28 (emphasis added). Although no state has yet legalized cannabis use for recreational purposes, with such regulations, an increasing number of jurisdictions have provided a way for consumers to easily obtain marijuana for loosely defined medical purposes.
Medical marijuana dispensaries offer a variety of cannabis strains, each with a different advertised “high” based upon variable proportions of Δ-9-THC and other constituents. The Δ-9-THC content of medical marijuana is about twice that of “street” marijuana, even with the latter’s Δ-9-THC content rising to >10% over the past 15 years.29,30 Therefore, medical marijuana is not only legal, but generally offers a more potent Δ-9-THC dose than typical street marijuana.
A single case of psychosis emerging in the context of medical marijuana has been reported in the literature.31 A 24-year-old man with mild, transient psychotic symptoms switched from street cannabis to medical marijuana for its superior potency and to conform with the law. He obtained a physician’s recommendation based on diagnoses of “posttraumatic stress disorder” and “pain.” After several months of increasingly frequent medical marijuana use, he developed florid and persistent psychotic symptoms necessitating antipsychotic medication, and was diagnosed with schizophrenia.
Although causality cannot be established based on this report, taken together with evidence that higher-potency cannabis is associated with a greater risk of psychotic emergence,32 this case raises concerns about the iatrogenic and psychotoxic liability of medical marijuana use among those vulnerable to psychosis. Policy decisions about medical marijuana and its use among patients with psychiatric illness must be informed by evidence of its psychotic potential.
Synthetic cannabinoids
Synthetic cannabinoids were developed in the 1960s for research purposes and potential clinical applications, but have not been FDA-approved for therapeutic use.33 Over the past 5 years, however, a variety of “herbal incense” products bearing names such as “Spice,” “K2,” and “Aroma” have emerged in Europe and the United States that contain botanicals laced with synthetic cannabinoids (Table 2).
Although herbal incense products are labeled “not for human consumption,” they are sold by “head shops” and on the Internet without age restrictions and typically are purchased for the sole purpose of ingesting them, usually by smoking. Their desired effects resemble cannabis intoxication, including sedation, relaxation, altered consciousness, and euphoria. The products initially had the added appeal of being legal and undetectable in routine drug screening. Although not listed among the product’s ingredients, chemical analyses confirmed these products typically contained 1 of 3 families of synthetic cannabinoid1 and cannabinoid2 (CB1/CB2) receptor agonists, designated by the prefixes JWH-, CP-, and HU-.34 The compounds most commonly found in these analyses (JWH-018; CP-47,497; HU-210) have significantly greater potency (ie, CB1 receptor affinity) compared with Δ-9-THC.33,34
The growing popularity of herbal incense products has prompted health concerns based on reports of emergency presentations for adverse effects, including tachycardia, agitation, excess sedation, and loss of consciousness.33,35,36 In addition, 8 anecdotal reports of psychosis associated with herbal incense (with a total of 33 patients) have emerged since 2010 (Table 3). Among them, a variety of psychotic symptoms are described in patients ranging in age from adolescence to adulthood, both with and without histories of psychosis. For those without a pre-existing psychotic disorder, symptoms were typically self-limited.