Omega-3's as Antidepressant in Pregnancy

(letter)  Chiu CC, Huang SY, Shen WW, Su KP  Omega-3 fatty acids for depression in pregnancy.  Am J Psychiatry. 2003 Feb;160(2):385

This is the story of a woman in China who had a previous depression during pregnancy, lasting 9 months after the pregnancy, and finally then recovering -- without medication treatment.  Then she had two more episodes of depression while not pregnant, which responded to paroxetine (Paxil in the U.S.).

But when she became depressed during another pregnancy, she did not want to take medications for fear that they might harm her baby.  So, these doctors offered her the Omega-3 option, as they had been studying this approach in other patients (see the Omega-3 table:  Su, 2003). 

The dose was 4 g of ethyl eicosapentaenoic acid (EPA) and 2 g of docosahexanoic acid (DHA) per day.  Note that if you were taking a 1-gram fish oil capsule containg a total of 250 mg of Omega-3's (e.g. Costco's Kirkland brand), you would have to take 24 capsules per day to get this dose.  Burp. 

She did not improve until the 4th week of this treatment, when her depression score (HAM-D) went from 29 to 18.  By week 6 her score was 10, and she reached "remission" -- a depression score of 7 -- by the 10th week. 

Was it really the omega-3's that did this?  The doctors concluded yes:

Since the patient received regular follow-up for 6 weeks before treatment with omega-3 polyunsaturated fatty acids, it is unlikely that the remarkable improvement was due to the clinical attention of regular visits. Because the patient had a depressive episode during her first pregnancy and after childbirth, we do not think that she had a spontaneous remission from this episode.

In their conclusion, the doctors  wonder whether the developing fetus might actually take omega-3's from mother, lowering her levels, and making her more susceptible to depression (numbers in parentheses are in their letter's references):

Reduced maternal DHA status after the second trimester (4) is associated with a high demand from the developing fetus for the rapid formation of its brain. Empirical studies of polyunsaturated fatty acids in the tissues (5), data from epidemiologic surveys (6), and results of therapeutic trials of polyunsaturated fatty acids (1) suggest that a deficit in omega-3 polyunsaturated fatty acids might cause major depressive disorder (7, 8). Supplementation with omega-3 polyunsaturated fatty acids is thought to have protective effects for pregnancy outcome in high-risk pregnancy (2).

Dosage of EPA in psychiatry

The researchers have found that, in order to achieve a clinical change for the better, at least 500 mg of pure EPA is needed. A usual time lag is three months. Different conditions seem to respond to different daily EPA doses as follows:

500 mg per day may suffice for some children with learning difficulties, ADHD and related syndromes.

500 to 1000 mg as complementary treatment for epilepsy, depending on the individual´s response.

1000 mg (1 g) seems alleviate or cure depression, chronic fatigue and anorexia nervosa.

2000 mg (2 g) per day is required for the treatment of schizophrenia. Larger doses do not yield any further benefit.

The reader may ask, whether it is not possible to get enough EPA from the diet. The answer is yes, if you are healthy, and eat 2 to 3 meals weekly including salmon or corresponding fatty fish. But if we are talking about neurological or psychiatric condition's the answer is no. 100 g of salmon contains about 170 mg EPA and 380 mg DHA. In other words, in order to get 500 mg EPA per day, one would need to intake 300 g salmon, and to get 1000 mg 600 g salmon, and to get 2000 mg, 1,2 kg salmon, would be required respectively, day after day, year out, year in.