A staff member asks the nurse how lithium works biologically as a mood stabilizer. Which of the ...

A staff member asks the nurse how lithium works biologically as a mood stabilizer. Which of the following mechanisms correctly explains the action of lithium?
 
  A) Lithium is a central nervous system stimulant that blocks irrelevant thoughts and impulses.
  B) Lithium reverses the deficiencies of the neurotransmitters dopamine, serotonin, norepinephrine, and
  acetylcholine.
  C) Lithium potentiates the effects of GABA, an inhibitory neurotransmitter.
  D) Lithium inhibits a second messenger system whose overactivity may be responsible for mania and
  depression.