1.   In the long term production of serotonin is reduced, leading to depression most suicides have low serotonin levels.

2.   A report in the October issue of Nature Genetics says that low serotonin levels have been implicated in negative moods, including depression and social phobias.

3.   Depression and low serotonin levels have long been linked.

4.   In addition to causing mood swings, some researchers believe low serotonin levels also cause PMS sufferers to crave and consume large quantities of carbohydrate-rich foods.