So-called 'synthetic marijuana' linked to serious health problemsSCBs are often sold as safe alternatives to marijuana that, because of their chemical structures, will not be discovered through standard drug screenings. This feature makes them popular among groups who want to elude detection, such as adolescents and military personnel. SCBs are also more potent than ?9-THC; "these are highly efficacious drugs; they tend to activate the CB1 receptor to a greater degree than we can ever get to with THC from marijuana," says William E. Fantegrossi, a behavioral pharmacologist at UAMS. As a result, some users turn to them to achieve a more intense high. A range of both acute and long-term adverse effects of SCB use are reported in clinical case studies, including seizures and convulsions, kidney injury, cardiotoxicity, strokes, anxiety, and psychosis in susceptible individuals, as well as tolerance, withdrawal, and dependence. Twenty deaths have also been linked to SCB use.