[1] He is remembered for research done at Görlitz with his associate Ewald Hecker (1843–1909) involving studies of young psychotic patients.

In their analyses of mental disorders, Kahlbaum and Hecker introduced a classification system that used descriptive terms such as dysthymia, cyclothymia, catatonia, paraphrenia and hebephrenia.

[2] Kahlbaum referred to Jugendliche Irresein or "juvenile madness",[3] and stressed the importance of parental upbringing to prevent this condition from occurring.

In his research of catatonia, he published the monograph, Die Katatonie oder das Spannungsirresein, in which he characterizes the disorder as disturbance in motor functionality that represents a phase in a progressive illness that includes stages of mania, depression and psychosis that typically ends in dementia.

The eponymous "Kahlbaum's syndrome" is a catatonic symptom characterized by continuous and purposeless rhythmic repetition of words and sentences that are meaningless or insignificant (echolalia).