Although we’re only beginning to pull back the curtains that hide the inner workings of the human brain, we do know that several neurotransmitters (chemical messengers), including acetylcholine, GABA, norepinephrine, dopamine, and serotonin, help to regulate our moods and keep us happy.1-5 Why do brain levels of mood regulators fall in some people but not in others? We can’t fully answer that question although we know that genetics plays a major role.6-10 It may be that some of us are lucky enough to have large reserves of “happy” neurotransmitters in our brains, but others have just barely enough to keep a smile on their faces.
Although biochemistry is a big factor, we’re also affected by what happens to us in our lives. We’re all hit by unpleasant events that may cause brain levels of norepinephrine and dopamine to fall temporarily. People with naturally large reserves usually get through the troubling times with minimal difficulties, but those with initially low chemical levels are more likely to be affected.
St. John’s Wort (Hypericum perforatum extract) is a weak inhibitor of monoamine oxidase (MAO),80 which destroys monoamine neurotransmitters including dopamine in the brain and leads to low spirits. St. John’s Wort has also been shown to inhibit re-uptake of several neurotransmitters, such as serotonin, dopamine, noradrenaline, and GABA in the brain, and to reduce expression of interleukin-6.81-83 Each of these actions can contribute to alleviating low mood status by slowing the recycling of neurotransmitters needed for maintaining emotional balance. Flavonoids, hypericin and pseudo-hypericin, are the constituents thought to be associated with the benefits of St. John’s Wort. In particular, hypericin appears to be the active ingredient.84-86