Understanding the historical development of the terms will shed some light onto the origin of the term ‘disorder.’ Robert Spitzer, MD was the guiding force behind the sea of change of the 1980 DSM-III. Spitzer, initially trained in psychoanalysis as per the psychoanalytic hegemony in the mid-20th century, quickly decided that was not his calling. He gravitated to the realm of computer sciences and bio-metrics at Columbia where he began to work in the area of diagnosis.
Following the Stonewall riots for gay rights in 1969, the American Psychiatric Association was under increasing pressure to de-classify homosexuality as an official mental disorder as listed in the DSM-I & II.
Spitzer chose the term “disorder” which has continued to populate the current DSM-5. There is no other specialty of medicine that uses the term “disorder,” i.e., there is no cancer disorder, no heart disorder, no rheumatoid arthritis disorder, or diabetes disorder. In fact, psychiatry is the only medical specialty that has a diagnostic and statistical manual i.e., a DSM. Choosing the nebulous term “disorder” was intended to not offend various groups. (See Decker and Shorter in resources.)
New “disorders” appear to grow like weeds
I am unaware of any other specialty of medicine that has had such an exponential growth of diagnoses (”disorders”) since 1980 as has psychiatry. Our medical colleagues must be baffled as to how this takes place.
Some of these “disorders” are real diseases like schizophrenia and what we call today “bipolar”. Both of these diseases are more than 80% heritable.
“Heritability summary estimates were as follows: bipolar disorder (85%), schizophrenia (81%), Alzheimer’s disease (75%), cocaine use disorder (72%), anorexia nervosa (60%), alcohol dependence (56%), sedative use disorder (51%), cannabis use disorder (48%), panic disorder (43%), stimulant use disorder (40%), major depressive disorder (37%), and generalized anxiety disorder (28%).”
(O. J. Bienvenu, et.al., Psychiatric ‘diseases’ versus behavioral disorders and degree of genetic influence. Published online by Cambridge University Press: 12 May 2010)
Notice the DSM defined MDD and GAD to have low heritability rates and cannot be considered diseases. In fact, gene studies indicate they have considerable genetic overlap and cannot be considered separate entities.
This is an example of how DSM definitions with overlapping symptoms masquerade as separate “disorders,” i.e., they do not exist in nature like schizophrenia or Bipolar.
KS Kendler, Major depression and generalized anxiety disorder: Same genes and (partly) different environments – revisited, British Journal of Psychiatry 1996; 168(suppl 30): 68–75.
Kendler, K. S., et al (1992b) Major depression and generalized anxiety disorder: same genes, (partly) different environments? Archives of General Psychiatry, 49, 716–722
Both MDD and GAD were terms invented by Robert Spitzer prior to the DSM-III as a concession to the psychoanalytic establishment for eliminating Depressive Neurosis (i.e., chronic mild depression and anxiety), so doctors could continue to get reimbursed by insurance companies with other codes.