Epi-inositol: A potential antidepressant

Inositol is a simple polyol precursor in a second messenger system important in the brain. A double-blind controlled trial of 12 g daily of inositol in 28 patients with depression for 4 weeks found significant benefit for inositol compared to placebo on the Hamilton Depression Scale. Because many antidepressants are effective in panic disorder, 21 patients with this disorder completed a double-blind, placebo-controlled crossover treatment trial of inositol 12 g per day. Frequency and severity of panic attacks and severity of agoraphobia declined significantly with inositol treatment compared to placebo. Because serotonin reuptake inhibitors benefit obsessive-compulsive disorder (OCD) and inositol is reported to reverse desensitization of serotonin receptors, 13 patients with OCD completed a double-blind, controlled crossover trial of 18 g inositol or placebo for 6 weeks each. Inositol significantly reduced scores of OCD symptoms compared with placebo. Epi-inositol, an artificial stereoisomer of myoinositol, was found to have effects similar to those of myoinositol in reversing lithium-pilocarpine seizures and in reversing lithium-induced rises in cytidine monophosphorylphosphatidate in cultured cells as does myoinositol. We measured the behavior of rats in an elevated plus-maze model of anxiety after chronic treatment of 11 daily ip injections of epi-inositol, myoinositol, or control solution. Epi-inositol reduced anxiety levels of rats compared with controls, and its effect was stronger than that of myoinositol. Epi-inositol could be a more effective psychoactive drug than its natural analog. (C) 2000 Wiley-Liss, Inc.