Study completers represented 13 different countries and 42 of the 50 U.S. states. They were primarily male (83%), Caucasian (90%), and had never been married (67%). The majority (96%) had a high school level of education, and 48% had a college degree. At the time of survey completion, 47% were employed full time, 28% were students, 9% were unemployed, and 38% were subject to drug testing procedures.
Respondents endorsed lifetime use of a variety of licit and illicit drugs including: alcohol (92%), cannabis (84%), tobacco (66%), hallucinogens (37%), prescription opioids (34%), MDMA (29%), benzodiazepines (23%), amphetamines (22%), cocaine (17%), salvia divinorum (17%), heroin (7%), inhalants (7%), dissociative anesthetics (6%), methamphetamine (3%), and miscellaneous drugs (mephadrone, dextromethorphan, kratom; 12%). Spice was reported as the drug of choice among 21% of respondents, and 25% reported no plans for future Spice use.
3.2. Drug Supply
Respondents reported obtaining Spice products from retail vendors (e.g., head shops, gas stations/convenience stores; 87%), the Internet (38%) or from friends and/or relatives (29%). Though 49% of respondents reported living in an area where local legislation had been passed to ban Spice products or individual synthetic cannabinoids, only 2% reported obtaining Spice from an illicit drug dealer.
3.3. Characteristics of Spice product use
Mean (SD) age of first use of Spice products was 26 (9). Mean days of use in the past year was 67 (SD: 102; range: 0 – 365) and mean number of uses per day was 4 (SD: 4; range: 0–20). A subset of respondents endorsed regular Spice use, with 55% and 39% reporting use in the past month and past week, respectively. Spice products were primarily smoked (via pipe, cigarette, blunt, or water pipe/bong), though administration via vaporization, oral ingestion, and rectal ingestion were also reported. During an average episode, participants reported consuming a mean of 4.8 (4.2) “hits” or 1.0 (1.2) grams of product. The average duration of subjective intoxication lasted 93 (SD: 69, range: 10–360) minutes. The maximum amount consumed in a single episode was reported as 7.6 (5.8) “hits” or 1.5 (1.6) grams of product, and the greatest duration of intoxication lasted 170 (SD: 152, range: 10–780) minutes.
Spice use generally occurred alone (44%) or in small groups (42%), as opposed to large social gatherings (14%). Primary reasons for use were curiosity (78%), liked the effects (58%) and relaxation (48%), though 30% endorsed using Spice products to achieve intoxication while avoiding detection in drug urinalysis testing. Spice was used in conjunction with other drugs on at least one occasion by 65% of participants. Alcohol (54%), cannabis (40%), and tobacco (38%) were the most frequently reported drugs combined with Spice products.
3.4 Subjective effects of Spice products
Subjective effects of Spice products are provided in . Most respondents (85%) indicated that Spice products produced subjective effects similar to cannabis, and fewer than 10% reported similarities between Spice products and other licit and illicit drugs. Despite producing effects similar to marijuana, 54% of respondents reported Spice products did produce subjective effects that were unique and discernable from other licit and illicit drugs. The frequency of hallucinations (28%) following Spice product use is also greater than what would be expected for cannabis consumption.
Subjective Effects of Spice Products
Most respondents (87%) reported having a positive experience following use of a Spice product, though negative or unwanted effects following use were reported by 40% of the sample. The quantity of Spice product consumed did not vary significantly between respondents who did and did not have a history of negative effects. Interestingly, 11% reported that multiple uses of the same brand of Spice product resulted in variable and unpredictable effects.
3.5 Perceived safety of Spice products
The majority (88%) of participants were aware that Spice products contained chemical constituents that were added to a plant product to produce intoxication; however, 11% believed that Spice products contained only “natural herbs and spices” and 14% agreed that “If Spice products were not safe for human use, they would not be marketed and sold in stores.” Although most reported that Spice products were “generally safe for human use,” 68% also believed there was an inherent danger or harm associated with Spice product use. Mean (SD) rating of overall harm of Spice product use on a scale of 0 (not at all) to 10 (extreme) was 2.7 (2.3), with 18% of respondents endorsing “no risk” (0) and <1% endorsing “extreme risk” (10).
3.6. Spice use disorders and withdrawal
A subset of respondents met DSM-IV criteria for abuse (37%) and dependence criteria (12%). Using Spice in a hazardous situation was the most commonly endorsed abuse criteria (27%), and being unable to cut down or stop Spice use (38%), experiencing symptoms of tolerance (36%), using for longer periods than originally intended (22%) and having interference with other activities (18%) were the most commonly reported dependence criteria. Despite endorsing problems related to Spice use, none had ever sought or received treatment.
Withdrawal symptoms following cessation of Spice use were rare, and most prevalent among more frequent users. The most commonly reported withdrawal effects were headaches (15%), anxiety/nervousness (15%), coughing (15%), insomnia/sleep disturbance (14%), anger/irritability (13%), impatience (11%), difficulty concentrating (9%), restlessness (9%), nausea (7%), and depression (6%).