The second century C.E. Greek physician and philosopher Galen advised patients suffering from disorders of the spirit to bathe in and drink hot spring water. Modern day brain scientists have posited that Galen’s prescription delivered more than a placebo effect. Lithium has for decades been recognized as an effective mood stabilizer in bipolar disease, and lithium salts may have been present in the springs Galen knew.
Yet exactly how lithium soothes the mind has been less than clear. Now, a team led by Ben Cheyette, a neuroscientist at the University of California in San Francisco (UCSF), has linked its success to influence over dendritic spines, tiny projections where excitatory neurons form connections, or synapses, with other nerve cells. Lithium treatment restored healthy numbers of dendritic spines in mice engineered to carry a genetic mutation that is more common in people with autism, schizophrenia, and bipolar disorder than in unaffected people, they report today in Molecular Psychiatry. The lithium also reversed symptoms in these mutant mice—lack of interest in social interactions, decreased motivation, and increased anxiety—that mimic those in the human diseases.