Administration of inositol decreased signs
of depression in two animal studies. Several small human studies suggest that
inositol may be of value in the treatment of depression, particularly for those
who do not respond to antidepressant medications.
(Harry
Croft, MD (Psychiatrist) Medical Director)
What
is Inositol?
Inositol,
or Vitamin B8, is a water soluble fatty lipid that is required by the body for
the formation of healthy cells. Inositol has been shown to be effective in
treating some cases of depression, anxiety, OCD and other psychological
disorders that respond to serotonin uptake inhibitors.
Inositol is a naturally occurring isomer of glucose,
though it is generally considered to be a member of the B vitamin family. It is
a key intermediate in the intracellular phosphatidyl inositol second messenger
pathway activated by numerous serotonergic, cholinergic, and noradrenergic
receptors. In this capacity it serves as an important signal transduction
molecule, but inositol is also a structural component of cellular membrane
phospholipids. Research indicates that inositol is an effective and safe option
in the treatment of panic disorder, obsessive-compulsive disorder (OCD),
bulimia nervosa, binge eating and/or depression. Inositol's efficacy, in the
absence of side effects, makes this nutrient an attractive addition to
treatment plans for specific mood disorders. Following is a scientific review
of inositol for the treatment of mood disorders, including a discussion of its
anecdotal use for the treatment of insomnia and its cautioned use by pregnant
women for the prevention of neural tube defects and embryopathies.
Among
other reported benefits of inositol in clinical settings are:
- Reduction in the need for pain medication when
patients are given inositol. - Reduction of edema in treatment of scald burns.
- Relieving the symptoms of diabetic neuropathy.
According
to an abstract published by Lisa Colodny, Pharm D. and Ronald L. Hoffman, M.D.
about the clinical applications of inositol, “Inositol is now established as a significant mediator of calcium
mobilization in the endoplasmic reticulum. Modifying this mobilization of
calcium may be effective in treating some CNS disorders like Alzheimer's
disease, depression, panic disorder, obsessive compulsive disorder, and as an
analgesic for pain control. Likewise, its use to alleviate lithium-induced
adverse reactions is also promising.”
What
inositol Does?
Inositol is used in the production of inositol
triphosphate and diacylglycerol, both of which are molecules involved in the
system that allows communication between neurotransmitters and the interior of
cells. It is believed that a decrease in inositol could lead to a shortage of
these two molecules, causing mood-regulating neurotransmitters - such as serotonin,
dopamine and norepinephrine - not to be able to properly communicate with the
interior of brain cells. Supplementation with inositol could help depression by
improving the functioning of this.
So,
Inositol is a ‘second messenger’, triggering the release of calcium in cells.
It also is involved in the transmission of messages between neural cells and
the transport of fats within cells. It’s most important role seems to be in the
central nervous system, where it serves to help transmit messages along neural
pathways. Various studies have shown its efficacy in treating a number of
psychological disorders that seem to have a chemical basis, including bulimia,
OCD, depression and bipolar mood disorder. Inositol seems to be present in
greater concentration in the cells in and around the central nervous system,
including brain cells and retinal cells, and in other specialized cells such as
bone marrow and intestinal cells. It is also found in high concentration in
mother’s milk, leading to the possibility of a link to the immune system.
Because
of its role in cell health and neurotransmission, inositol is considered an
important nutrient, even though it is not technically a ‘vital’ nutrient or a
vitamin.
Health
Benefits of inositol
Inositol
has been used for some time in the treatment of several neurologically based
disorders. These include:
- Mild to
moderate depression. Patients treated with supplements of inositol showed a
definite improvement in several studies of depression.
Depressive patients generally have decreased levels of inositol in their
cerebrospinal fluid. Researchers now theorize that inositol produces
positive clinical results in patients with depression due to intracellular
phosphatidyl inositol serving as a second messenger for
5-hydroxytryptamine (5-H[T.sub.2]) receptor signaling mechanisms.
Serotonin selective reuptake inhibitors (SSRIs), a family of drugs
commonly used to treat depression, have a similar therapeutic profile to
inositol in that they inhibit serotonin reuptake in the synaptic cleft.
Levine et al. performed a double-blind, placebo-controlled trial for 28
days on 28 depressed patients using a large dose (12 grams per day) of
inositol. The Hamilton Depression (HAMD) Scale was used to evaluate
patients after the 28-day trial period, and a significant overall benefit
was confirmed in the inositol group compared to the placebo group. No
changes were noted in liver, kidney, or hematological function as a result
of the high-dose inositol supplementation.
- Obsessive-compulsive
disorder (OCD). In several studies, patients suffering from OCD and
related disorders showed relief of their symptoms when given supplements
of inositol.
Levine completed a review of
research studies using inositol on psychiatric patients. The review highlighted
some interesting findings with OCD patients. Serotonin plays a definitive role
in obsessive-compulsive disorder as confirmed by the effectiveness of SSRIs in
OCD patients and the fact that serotonin agonists exacerbate the syndrome.
Rahman and Neuman effectively reduced serotonin receptor desensitization via
the administration of myo-inositol.
These research findings, coupled with the knowledge that SSRIs have proven
beneficial in the treatment of OCD, influenced Fux et al. to complete a
double-blind, placebo-controlled, random, crossover treatment trial of inositol
on OCD. Thirteen patients, all of whom met DSM-III-R criteria for OCD,
completed the trial. Six patients began the trial on placebo and seven began
the trial on inositol (18 grams per day) for a total of six weeks for the first
phase and six weeks for the crossover phase. The researchers administered 18
grams of inositol rather than 12 grams (typical dose for depressive patients)
because OCD patients generally respond to higher relative doses of SSRIs than
is needed to effect change in most depressives. The OCD patients were free of
drug and alcohol abuse and had no evidence of diabetes or GI disorder. OCD was
assessed using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and
depression and anxiety were assessed using the Hamilton Depression Scale (HDS)
and Hamilton Anxiety Scale (HAS). The mean improvement in OCD symptoms from
baseline to six weeks was 5.9 for inositol versus 3.5 for placebo. This
indicates a measurable positive response of OCD patients to inositol.
- Panic
attacks. Clinical evidence suggests that large doses of inositol may reduce
the number and severity of panic attacks.
Panic attacks are recurring
attacks of severe anxiety without an apparent cause. Agoraphobia (irrational
fear and avoidance of crowds, travel, and multiple situations), depression,
alcohol abuse, and suicide are common symptoms and may be exacerbated by
post-traumatic stress. Current treatments usually consist of antidepressant
drugs and cognitive-behavioral therapy.
Antidepressant medications affecting serotonin metabolism are effective about
70% of the time for dramatic, short-term improvement of anxiety symptoms.
However, chronic residual symptoms often persist in the long term. 25-75% of
patients with panic disorder discontinue drug treatment because of side
effects, and these patients quickly relapse.
In one study, twenty-one patients diagnosed with panic disorder with or without
agoraphobia were given 12 grams of inositol per day or placebo. In the
treatment group, the severity and frequency of panic attacks declined
significantly with minimal associated side effects. The average number of panic
attacks per week in patients treated with inositol fell from 10 to 3.5 per
week. The researchers concluded that these results were "clinically
meaningful" in the management of panic attacks.
More recently, inositol was compared with the antidepressant fluvoxamine in the
treatment of panic disorder. This study represents a more stringent test of the
effects of inositol in treating panic disorder because it is the first to
compare inositol with an established antidepressant drug. In this study of 20
patients with panic disorder, inositol was found to be slightly but
significantly more effective than fluvoxamine in reducing the number of panic
attacks. Otherwise, it was comparable to fluvoxamine on all other measures
(HAS, phobia, and Clinical Global Impression (CGI) Scale). Since inositol
appears to be as effective as fluvoxamine, patients may prefer it and continue
to take it for the long term because side effects are extremely rare and mild.
Inositol in Diet
Fruits and vegetables that are especially rich in inositol
include: cabbage, beans, legumes, seeds, nuts, cantaloupe, bananas, raisins,
oranges and other citrus fruits. It is also found in wheat, cereal, oat flakes,
wheat bran, wheat germ, brown rice, brewer's yeast and unrefined molasses.
Inositol is also found in organ meats, such as
brain, heart and liver.
Dosage
The recommended doses for inositol generally fall in
the range of 6 to 20g per day, with 12g being the more usual dose. It is taken
in divided doses, two to four times a day.
Due to the potential risk of cycling, patients with
bipolar disorder should consult with their physician before supplementing with
inositol.
Side Effects and Limitations
Inositol is well-tolerated and appears to be quite
safe. Side effects may include: mild decreases in plasma glucose, flatulence
(gas), nausea, sleepiness, insomnia, dizziness and headache. There have been
some case reports of inositol-induced mania in bipolar patients. To date, there
have been no reports of toxicity or drug-drug interactions with inositol.
Inositol supplementation is not recommended for
pregnant women due to the fact that there is a risk of inducing uterine
contractions. It is not known if it is safe for breastfeeding women.
Is Inositol an Effective Treatment for
Depression?
Inositol is readily available in most health food
stores without a prescription and recommended for the treatment of a variety of
mental disorders, including depression.
Thus far, inositol has mainly been investigated as
an add-on to mood stabilizers and antidepressants for the treatment of the
depressive symptoms of bipolar disorder. Findings suggest that it may be at
least somewhat helpful for these patients.
It is not known whether inositol could also help
unipolar depression. Although two studies conducted using unipolar patients had
negative results, their sample sizes were too small to draw any definitive
conclusions. More research is
still needed to consider Inositol as effective solution for depression relief. The
good thing, however, to come of the trials was that the supplement was absolutely
safe and was not associated with any side effects.
Sources and Additional
Information:
