If you've ever wondered why medications like Zoloft (sertraline), Lexapro (escitalopram), Prozac (fluoxetine), Cymbalta (duloxetine), or Effexor (venlafaxine) are prescribed for depression or anxiety, it all comes down to tiny chemical messengers in your brain called neurotransmitters. Neurotransmitters are brain chemicals that help regulate your mood, emotions, energy, sleep, memory, motivation, and how you respond…