Do we need to replace categorical with dimensional diagnoses to make progress in psychiatry research? Mostly.
The 1950s was a golden era for psychopharmacology. Within short order, sedatives such as meprobamate (Miltown) became available for the treatment of anxieties, monoamine oxidase inhibitors for depressions, and neuroleptics for psychoses. The mechanisms of action of these compounds were efficiently traced to their effects at specific targets using then-emergent neuroscientific methods. Perhaps even more importantly than their immediate utility, these treatments ushered in an era of optimism that the chaotic psychiatric diagnoses of the day could be codified and defined according to relevant biological characteristics: schizophrenia became unmoored from its Kraepelinian/Bleulerian roots and was effectively the disease that responded to antipsychotics, depression became the disease that responded to antidepressants, anxiety was a disease that responded to anxiolytics, and bipolar disorder was the disease that responded to lithium therapy.
Yee CM, Javitt DC, Miller GA. Replacing DSM Categorical Analyses With Dimensional Analyses in Psychiatry ResearchThe Research Domain Criteria Initiative. JAMA Psychiatry. 2015;72(12):1159-1160. doi:10.1001/jamapsychiatry.2015.1900