Synthetic cannabinoids are man-made compounds that act through the brain's cannabinoid receptors (CB1 and CB2) to induce mind-altering effects. The CB1 receptor affects the dopamine system, which is thought to modulate psychotic symptoms (
1,
2). One common synthetic cannabinoid, JWH-018, has four times greater the affinity for CB1 than tetrahydrocannabinol, the primary cannabinoid found in cannabis. Another synthetic cannabinoid, AM-694, has recently begun to appear on the illicit market and is associated with hallucinations and delirium (
2). In contrast, cannabis contains cannabidiol, an antagonist to both CB1 and CB2 that may protect against psychosis but is not found in synthetic cannabinoid mixtures being sold (
1–
3). This may explain why synthetic cannabinoids are associated with higher risk of episodic psychosis following use than cannabis (
3,
4). In addition to psychosis, there have been multiple other reported morbidities associated with synthetic cannabinoids usage, including tachycardia, hypertension, cardiac arrest, pulmonary infiltrates, renal impairment, seizures, and suicidality (
5,
6).
Originally developed in the 1970s (
5), synthetic cannabinoids are now being covertly synthesized, sprayed on plant material, and sold in convenience stores as incense or potpourri under names such as K2, spice, and Scooby snacks. Illicit laboratories have circumvented issues of legality by introducing novel compounds that differ slightly from previous versions, especially when older versions were outlawed. The Synthetic Drug Abuse Prevention Act of 2012 now enables the Food and Drug Administration to ban all cannabimimetic substances, allowing for the inclusion of current and unreleased synthetic cannabinoids. Therefore, all synthetic cannabinoids are now technically illegal for human consumption in the United States. However, they continue to be marketed under the guise of use as incense or potpourri.
Few studies have explored why and how individuals use synthetic cannabinoids. In one survey of users, 54% of participants reported that the intoxication from synthetic cannabinoids, which often includes hallucinations, is unique (
7). More than half reported use in group settings, and one-third reported an inability to decrease usage and development of tolerance. A New Zealand study examining the use of synthetic cannabinoids in psychiatric patients on a forensic inpatient unit (
1) revealed that patients preferentially used synthetic cannabinoids due to easy procurement, increased potency compared with marijuana, non-detection in urine, and beliefs that they were safe because they were legal and sold as “herbal” products.
In 2014, staff at a local Boston Department of Mental Health transitional housing shelter noted a rapid increase in synthetic cannabinoid usage among residents, who discussed their use in the shelter's substance use group therapy sessions. We investigated shelter resident attitudes about synthetic cannabinoids and their use patterns in order to find potential points of intervention to increase awareness of the dangers of synthetic cannabinoids and decrease resident usage.
Method
Study Procedures and Participants
This study was approved by the Partners Human Research Committee (protocol #P000088; Massachusetts General Hospital). In December 2014, residents from an 80-bed Boston Department of Mental Health transitional housing shelter who were ≥18 years of age and who openly acknowledged synthetic cannabinoid use were recruited. Written, informed consent was obtained from participants. In calculating our ideal sample size, for the study's total population we used the number of homeless individuals in Boston being treated for substance use disorders in 2015 (N=614) (
8) to serve as a proxy for the number of homeless synthetic cannabinoid users, although this likely overestimates the number. Using Slovin's formula (
9), n=N/(1+Ne2) (where n=sample size, N=total population, and e=error tolerance, with an error tolerance of 5% and a total population of 614), the calculated ideal sample size was 242 participants. However, only 10 individuals were identified as meeting inclusion criteria, and two declined to participate.
Data Analysis
Semi-structured interviews were conducted addressing subjects' histories of substance use, their perceptions of the effects of synthetic cannabinoids, their reasons for use, and their knowledge of associated risks. Interview contents were de-identified and transcribed during the interviews. Transcripts were reviewed and coded for themes/categories. Codes were compared, and those on which there was consensus were included in the final analysis.
Results
Demographic Characteristics
Eight participants were included in the study, of which five were males (63%), with a mean age of 38 years (range: 22–61 years). Five participants (63%) were diagnosed with primary mood disorder and three (37%) with a primary psychotic disorder. All were prescribed antipsychotic medications. One-half of the participants in the group were also misusing alcohol and marijuana. Half of participants used synthetic cannabinoids daily, with the amount used ranging from one to 10 joints per day. The duration of synthetic cannabinoid use ranged from 2 to 12 months.
Knowledge
Six participants (75%) believed that possession and use of synthetic cannabinoids was legal. The most commonly used descriptors for synthetic cannabinoids by participants were “flowers,” “potpourri,” and “incense.” Seven participants (87%) understood that synthetic cannabinoids consist of plant material sprayed with synthetic chemicals, while one believed that they were natural substances. Three participants (32.5%) believed that there were no health risks associated with use.
Usage Patterns
Interestingly, most individuals started using synthetic cannabinoids after moving to the shelter and were not aware of their existence previously. One participant (13%) reported previous use at a nearby shelter. Half reported daily synthetic cannabinoid use, most commonly in the form of a joint. Nearly all participants (N=6 [75%]) used synthetic cannabinoids in groups rather than alone. Participants preferred synthetic cannabinoids to marijuana due to lower cost (63%), easier accessibility (38%), and subjectively more desirable intoxication (38%). Six users (75%) obtained the substance directly from convenience stores. Two users (25%) were supplied with synthetic cannabinoids by individuals selling from within the shelter.
Effects
Perceived positive effects of intoxication brought on by synthetic cannabinoid use, as well as negative effects, are summarized in
Table 1. Five participants (63%) reported increasing tolerance. Four participants had attempted to discontinue use, three of whom also reported withdrawal symptoms. These symptoms included craving (N=2 [66%]), cough (N=2 [66%]), irritability (N=2 [66%]), and anxiety (N=2 [66%]).
Discussion
Since their arrival on the recreational drug scene in 2004, synthetic cannabinoids have rapidly increased in popularity. Simultaneously, concern has mounted about their negative effects. We sought to learn why, in a shelter population of chronically mentally ill individuals, synthetic cannabinoids are used to the exclusion of other substances. We were also interested in assessing participants' knowledge of synthetic cannabinoids and their risks, as a way to inform potential strategies to decrease use. Study limitations include a small sample size and retrospective design.
Multiple factors promoted the use of synthetic cannabinoids in the study population, including perceived legality and safety, easy access, and low cost. Additionally, their use appears to result in a desirable state of intoxication that consists of increased relaxation and sociability, which may be particularly valued in a population in which social interactions can be anxiety- or paranoia-provoking. These reasons are similar to those of a 2012 survey of users who reported that curiosity, positive drug effect, and relaxation were primary reasons for use (
7).
Some participants reported tolerance and possible withdrawal, indicating likely dependence. A study in mice demonstrated that the synthetic cannabinoids JWH-073, 081, and 210 have psychological dependence potential (
10). A study of patients requesting detoxification services due to synthetic cannabinoid withdrawal revealed that agitation, irritability, anxiety, and mood swings were the most common components of withdrawal (
11). In line with this, participants in our study reported withdrawal symptoms that included craving, irritability, and anxiety.
With the passage of recent U.S. federal legislation now making possession of synthetic cannabinoids illegal, there is new potential for intervening in their sale. However, enforcement of these laws has been inconsistent. Clinicians in New Zealand noted a decrease in patient visits for treatment of synthetic cannabinoid withdrawal following their outlaw (
12). Therefore, informing patients about their illegality may be one approach to decreasing usage. Given that participants were using other substances simultaneously, it would be prudent for providers to screen for the use of synthetic cannabinoids in patients already known to be misusing other substances. Additionally, nearly half of the participants believed that no potential risk to their health from using synthetic cannabinoids exists. Thus, patients who are actively using synthetic cannabinoids would benefit from further education about the dangers of these substances.
Acknowledgments
The authors thank Maithri Ameresekere, M.D., and Derri Shtasel, M.D., for their assistance with the design of this study, as well as their editorial assistance