1.   New thinking on sadness suggests that it is the result of depressed serotonin levels.

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

3.   At least Carrie Bradshaw understands what a few good confidantes and a new pair of shoes can do for serotonin levels.

4.   A lower serotonin level, coupled with testosterone, tends to make boys more aggressive.

5.   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.

6.   Alcoholism, sleeplessness, sexual deviance and other impulse-control disorders also have been linked to low serotonin levels, which may result from a genetic defect.

7.   Compulsive behaviors like hand-washing can be substantially reduced with the help of drugs that affect serotonin levels in the brain.

8.   Controlling serotonin levels might provide one solution.

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