english: On a more microscale, depression is associated  with a few things: the abnormal transmission or depletion of certain neurotransmitters, especially serotonin, norepinephrine, and dopamine, blunted circadian rhythms, or specific changes in the REM and slow-wave parts of your sleep cycle, and hormone abnormalities, such as high cortisol and deregulation of thyroid hormones.
non_english: Na nižem nivou, depresija se vezuje za nekoliko stvari: abnormalno prenošenje ili istrošenost određenih neurotrasmitera, naročito serotonina, norepinefrina i dopamina, izmenjeni cirkadijalni ritmovi, ili specifične promene REM i sporotalasnih delova ciklusa spavanja, kao i hormonalne abnormalnosti, kao što je visoki kortizol i deregulacija tiroidnih hormona.