31. substances categorized as an opioid:
a. slow down the central nervous system
b. speed up the central nervous system
c. release the hormone dopamine
d. both a and c

Depression is lifelong, though you can get medication to with it. the difference between sadness and depression is that sadness lasts a little bit, depression last a long time and it goes on and off. people usually get depression through experiences they have been through, or genetics.