The carbocyclic sugar myo-inositol is vital during childhood brain development, and has been associated with reduced anxiety and panic attacks in adolescents. Benefits have also been observed in several adult human studies.

For example, myo-inositol supplementation has been shown to significantly aid adults with obsessive-compulsive disorder, panic attacks, and depression. Depression has been linked to low brain levels of myo-inositol.

One study of major depression suffered by people not on any psychiatric medications demonstrated significantly lower levels of myo-inositol in brain areas such as the prefrontal cortex and anterior cingulate cortex.

Another study of 19 adolescents — also not taking medications — used functional brain scanning which discovered that these depressed young men had significantly lower myo-inositol levels in specific parts of their brain (the dorsolateral prefrontal cortex and anterior cingulate cortex), especially if their depression was associated with sleep disorders.

Yet another study examined metabolic brain scanning of 22 patients with major depression who were not on any psychotropic medication compared to 27 healthy matched control subjects. The depressed patients demonstrated statistically significant reductions in myo-inositol in specific brain areas (the medial prefrontal cortex and amygdala). Significantly low concentrations of myo-inositol were also found in the prefrontal cortex of bipolar patients who had committed suicide.

Sleep disturbance is strongly associated with depression. In one study, researchers examined 60 pregnant women with sleep problems and found that giving them 2 grams of myo-inositol and 200 mcg folic acid for 10 weeks significantly improved the quality of their sleep — both in terms of duration and overall restfulness — compared to other women who took a placebo.

Much earlier studies demonstrated problems with myo-inositol in depressed patients. For example, research from 1978 demonstrated very low levels of myo-inositol in the spinal fluid of depressed patients.

More than a decade later, a study of 11 depressed patients who had not responded to treatment with conventional antidepressants demonstrated dramatic improvement when they were given 12 grams of myo-inositol. These researchers showed that supplementing orally with myo-inositol significantly raised its levels in the spinal fluid, indicating that there were high levels in the brain.