Only 70% of patients respond to current treatments for
panic disorder, and many discontinue drugs because of side effects. myo-
Inositol, a natural isomer of
glucose and a precursor for the second-messenger
phosphatidyl-inositol system, has previously been found superior to placebo in the treatment of depression,
panic disorder, and
obsessive-compulsive disorder (OCD), but a direct comparison with an established
drug has never been performed. A double-blind, controlled, random-order crossover study was undertaken to compare the effect of
inositol with that of
fluvoxamine in
panic disorder. Twenty patients completed 1 month of
inositol up to 18 g/day and 1 month of
fluvoxamine up to 150 mg/day. Improvements on Hamilton Rating Scale for Anxiety scores,
agoraphobia scores, and Clinical Global Impressions Scale scores were similar for both treatments. In the first month,
inositol reduced the number of
panic attacks per week (mean and SD) by 4.0 (2) compared with a reduction of 2.4 (2) with
fluvoxamine (p = 0.049).
Nausea and tiredness were more common with
fluvoxamine (p = 0.02 and p = 0.01, respectively). Because
inositol is a natural compound with few known side effects, it is attractive to patients who are ambivalent about taking psychiatric medication. Continuing reports of
inositol's efficacy in the treatment of depression,
panic disorder, and OCD should stimulate replication studies.