Schizophrenics have a higher rate of marijuana abuse than the general population. Many say that the drug eases their symptoms. Daniele Piomelli thinks he knows why. His answer may inspire new pharmaceuticals that harness the brain's own regulatory chemistry to treat mental disorders.
Piomelli, a pharmacologist at the University of California at Irvine, became interested in the mental effects of marijuana in 1992, when scientists discovered that the brain produces anandamide, a compound similar to THC, the active component in marijuana. His research suggests anandamide is the body's response to overproduction of dopamine, a brain-signaling chemical. Excess dopamine interferes with the transmission of nerve impulses and produces psychotic symptoms. Anandamide helps restore order by countering the effects of dopamine in the brain. THC appears to do the same.
But don't expect to see psychiatrists prescribing marijuana for their patients. "Marijuana, like all the antipsychotic drugs on the market, has a nonspecific sedative effect on the brain's dopamine levels," Piomelli says. He's looking for drugs to enhance the body's natural anandamide levels. Such medicines could combat a variety of disorders characterized by surges of dopamine-not just schizophrenia but also autism, Tourette's syndrome, and Huntington's disease.