At least seven people staying at a District of Columbia homeless shelter had to be hospitalized after overdosing on synthetic marijuana, re-igniting concerns about the risks of \u201cfake pot.\u201d The story underlines the problem of synthetic marijuana\u2014often labeled \u201cnot for human consumption\u201d\u2014and shows, yet again, that its \u201cnatural\u201d appearance and apparent similarity to marijuana are not indicative of the risks of the substance. Its abuse can lead to anxiety, paranoia, irregular heartbeat, seizures and even death, and despite increasing knowledge of its risks, some users\u2014like those at the D.C. homeless shelter\u2014still put themselves in danger by trying the drugs. What Is Synthetic Marijuana? Synthetic marijuana (often called \u201cspice\u201d) is a mixture of inactive plant matter and \u201cdesigner\u201d cannabinoid (marijuana-like) drugs, used in much the same way as marijuana. The sellers of such substances make them out to be \u201cnatural,\u201d but in fact the active components of the drugs are synthetic chemicals sprinkled on top of the plant matter, and there is considerable variation in the chemicals used and the amounts added. The \u201cdesigner\u201d nature of the chemicals means that they bear some similarity to the active components of natural marijuana, but their chemical structures have been sufficiently altered so they\u2019re technically not covered by the same laws. This means that while they have similar effects, they\u2019re fundamentally different than marijuana and have a range of (often unpredictable) effects. In particular, it\u2019s known that synthetic pot interacts with the same parts of the brain as marijuana, but binds to the receptors much more strongly, leading to more extreme effects. The drugs can produce similar effects to pot\u2014such as relaxation and euphoria\u2014but in many cases they\u2019re more severe, as are negative effects like paranoia, anxiety and hallucinations. Five of the most common chemicals used in synthetic marijuana have been classified as Schedule I controlled substances by the Drug Enforcement Administration, but the manufacturers of the drugs can simply alter the chemicals used to re-open the legal loophole that allows them to be sold. Hospitalizations at a Homeless Center The story from D.C. is just the latest in a string of serious reactions to synthetic marijuana. According to reports, the drugs were being sold near the homeless shelter and, after several people smoked the substances, nearly a dozen began showing signs of overdose, with seven taken to hospitals but others refusing treatment. A spokesman for the D.C. Fire and Emergency Medical Services Department said they were all expected to survive. A Fox 5 reporter found packages labeled \u201cBizarro\u201d on the ground, and fire officials said it was the brand to blame for the overdoses, but other reporters found different versions of the substance at the scene, too. Regardless of the specific product, the overdoses underline the uncertainty of the effects of the drugs. Someone might experience no negative effects the first time he tries synthetic pot, but might overdose the next time and need treatment in a hospital. Mayor Muriel Bowser said, \u201cSynthetic drugs are illegal and dangerous. These drugs present a clear danger to the public. My administration is committed to working with all relevant government agencies, residents, community organizations and the council to crack down on the distribution and consumption of these dangerous synthetic drugs.\u201d A statement to Fox 5 from the Metropolitan Police Department identified synthetic drugs as one of the \u201ctop 5 threats we face in public safety over the next several years,\u201d and said that, \u201cwe have officers working in the immediate area of the shelter to provide more presence, and will continue to work with DC Protective Services to address the issues around the building.\u201d Risks of Synthetic Marijuana As this story indicates, the biggest risks of synthetic marijuana are its unpredictability and the lack of knowledge about the effects a specific version may have. Similarly, the long term risks of spice abuse are ultimately unknown. Callers to poison control centers have reported rapid heart rate, hallucinations, confusion and agitation after smoking synthetic marijuana, and other known effects include increased blood pressure, reduced blood supply to the heart and even heart attacks. Other serious potential effects of the drugs include seizures and death. In addition, reports of tolerance and withdrawal in regular users provide strong suggestions that synthetic marijuana is addictive. Although steps have been taken to reduce the use of synthetic marijuana\u2014including making many of the included substances illegal\u2014and to raise awareness of its risks, the story from D.C. indicates that the problem hasn\u2019t disappeared. Whether in the form of \u201cBizarro,\u201d \u201cK2\u201d or any one of a cornucopia of brands, synthetic marijuana is both dangerous and unpredictable, and continuing to raise awareness of its risks and attempting to close remaining legal loopholes is essential. If you know someone who smokes synthetic marijuana, it\u2019s important to inform him or her of the risks, stress that it can be addictive and suggest that he or she find help to stop using it. Make no mistake: \u201cfake pot\u201d is a very real problem.