• The incidence of psychosis in 19,059 tuberculous patients in the year 1950 was compared with that in 18,261 tuberculous patients in 1953. Although the introduction of isonicotinic acid hydrazide therapy intervened between these two years, no significant difference in the incidence of psychosis was discovered.
A further comparison was made, in a group of 156 psychiatric patients with tuberculosis, between 79 patients who had received either isoniazid or iproniazid and 77 who had not received either drug. The distribution of various types of mental disturbance within the two groups was about the same. Six detailed case-histories and the tabulated data from 20 additional patients show that generally the mental disturbances ran their irregular courses of remissions and relapses without any evident relation to this medication.
These and other data cited lead to the conclusion that isoniazid therapy did not demonstrably increase the incidence of psychosis in tuberculous patients and that a history of mental disorder in a tuberculous patient does not contraindicate the use of this drug.
Zitrin A, Thompson DS. EFFECTS OF ISONICOTINIC ACID HYDRAZIDES ON MENTAL STATUS OF TUBERCULOUS PATIENTS. JAMA. 1956;161(3):204-210. doi:10.1001/jama.1956.02970030022006