Nearly half the juveniles and one-quarter of the adults arrested in San Diego County last year reported having used the synthetic drug spice, the San Diego Association of Governments reported Monday.
SANDAG, the regional planning agency, has been querying juvenile arrestees about spice use since 2011 and adults since 2012 as part of its substance abuse monitoring program.
While the 2015 figure for juveniles -- 48 percent -- is roughly the same as when the questioning started, the self-reported use of spice among adults has steadily climbed from 16 percent in 2012 to 24 percent last year, according to SANDAG data.
Breaking down adult use further, 35 percent of arrestees under 25 had tried the drug. The portion drops to 15 percent for ages 25-39 and 9 percent for those 40 and older.
The San Diego City Council last month tentatively voted to ban the manufacture, possession, distribution or sale of synthetic drugs like spice -- taking the action because of holes in state laws that allow makers to alter chemical compositions to avoid law enforcement. A second reading is scheduled for Tuesday.
Chula Vista, El Cajon, Encinitas, Oceanside and the county of San Diego have taken similar steps.
According to a city of San Diego staff report, emergency medical personnel responded to 650 cases of medical distress caused by spice between November and March, around two-thirds in a swath of the city running from Barrio Logan through downtown to Hillcrest. Downtown and East Village saw about half the cases.
Investigators viewing surveillance camera footage said they saw several of the users become incapacitated and unconscious immediately after ingesting spice, according to the city report. Some began stumbling and had difficulty standing or walking, and held onto the side of a building, a nearby tree, newspaper stand or some other sturdy object to prevent falling.
Authorities said emergency medical personnel were sometimes met by violent responses from spice users too incoherent to realize someone was trying to help them.
The SANDAG study found that 83 percent of juveniles and 62 percent of adults who had tried spice did so as an alternative to marijuana, and that 43 percent of juveniles and 38 percent of adults used it to avoid a positive drug test.