MAOIs started off due to the serendipitous discovery that iproniazid was a potent MAO inhibitor (MAOI).  Originally intended for the treatment of tuberculosis, in 1952, iproniazid's antidepressant properties were discovered when researchers noted that the depressed patients given iproniazid experienced a relief of their depression. Subsequent in vitro work led to the discovery that it inhibited MAO and eventually to the monoamine theory of depression . MAOIs became widely used as antidepressants in the early 1950s. The discovery of the 2 isoenzymes of MAO has led to the development of selective MAOIs that may have a more favorable side-effect profile. 
During this period Lovecraft revived his earlier scientific periodicals.  He endeavored to commit himself to the study of organic chemistry , Susie buying the expensive glass chemistry assemblage he wanted.  Lovecraft found his studies were hobbled by the mathematics involved, which he found boring and would cause headaches that would incapacitate him for a day.  Lovecraft's first poem that was not self-published appeared in a local newspaper in 1912. Called "Providence in 2000 .", the poem envisioned a future where proper people of English heritage were displaced by immigrants.  Surviving unpublished poems from this period, most notoriously "On the Creation of Niggers", were also emblematic of the xenophobia and racism inherent in much of Lovecraft's later work.