They got rid of them because they were deemed non-helpful. Treatment was identical in every subtype....no research was done on any of the subtypes...the trend is the opposite now it's the schizophrenia spectrum like the autism spectrum if anything they put sz sza and szpm together in research studies because for the most part you get equivalent treatment. Some of the most recent studies even include bipolar but usually they treat that as a separate cluster...actually the NIMH which is in charge of research has stopped requiring dsm terms in its applications because they don't represent distinct biological disorders. It's like the common cold...there are 200 separate types of virus that cause the cold...if we were trying to find one thing that would cure the cold we couldn't do it except for symptoms which are in common. So things are moving to the genetic level where there are hundreds of different mutations that may have an impact.