Vitamin B6 is an absolutely vital component in the conversion of tryptophan to serotonin. Not only that, but in order for tryptophan to be metabolized properly, it requires the presence of this vitamin. Therefore, an insufficient vitamin B6 intake is responsible for both low tryptophan and serotonin levels. Ever increasing research evidence is associating a low vitamin B6 intake with depression (23-26), a low tryptophan level with both depression aggression (27,28) and low serotonin levels with depression, aggression and suicidal behavior (29, 31).

Vitamin B6 supplements, up to 30mg per kg body weight, are particularly useful in treating children suffering from hyperactivity (32-34). Similarly, in treating autistic children (32, 35, 36). One double-blind crossover study on 16 autistic children found that their behavior improved whilst on vitamin B6 supplements and consequently deteriorated on withdrawal (35).

Vitamin B6 has been shown to be an effective remedy for depression associated with oral contraception and menopause. It has been reported that several studies have carried out estimating that many women become depressed because the hormones are depleting their bodies of vitamin B6. 

23. Stewart JW et al: Low B6 levels in depressed outpatients. Biol psychiatry, 19(4):613-616, 1984

24. Russ C et al: Vitamin B6 status of depressed and obsessive compulsive patients. Nutr Rep Int, 27(4):867-873, 1983

25. Carney M et al: Thiamin and Pyridoxine lack in newly admitted psychiatric patients. Br J Psychiatry, 135:249-254, 1979

26. Nobbs B: Pyridoxal phosphate status in clinical depression. Lancet, 1:405, 1974

27. Young SN et al: The therapeutic action of tryptophan in depression, mania and aggression. In: Progress in Tryptophan and Serotonin Research. Eds: HG Schlossberger et al. Walter de Gruyter, UK, 1984

28. Volavka J et al: Tryptophan treatment of aggressive psychiatric in-patients. Biol Psychiatry, 28(8):728-732, 1990

29. Van Praag HM: Depression. In: Neurotransmitters and CNS Disease. A Lancet Review, 1982

30. Brown GL et al: Aggression, suicide and serotonin. Am J Psychiatry, 139:741-746, 1982

31. Virkkunen M: Aivojen seretooni ja aggressiivisuus Duodecim, 102:850-852, 1986

32. Austin S: The truth about vitamin B6 safety. Int J Alt & Compl Med, 15(8):25-27, 1997

33. Coleman M et al: A preliminary study of the effects of pyridoxine administration in a subgroup of hyperkinetic children: A double-blind crossover comparison with methylphenidate. Biol psychiatry, 14(5):741-751, 1979

34. Bhagavan HN et al: The effect of pyridoxine hydrochoride on blood serotonirt and pyridoxal phosphate contents in hyperactive children. Pediatrics, 55:437-441, 1975

35. Rimland B et al: The effect of high doses of vitamin B6 on autistic children: A double-blind crossover study. Am J Psychiatry, 135:472-475, 1978