Drug abuse in chronic headache: a clinico-epidemiologic study.

Among the patients referred to the Headache Centre in Parma between 1979 and 1984, 95 (5%) were found to be drug abusers, having taken analgesics every day for at least a year. They had had chronic headache for at least 12 months: migraine with interparoxysmal headache in 83.1% and chronic tension headache in 16.9%. Almost all patients were combination-analgesics abusers, and only about a quarter of them were taking ergotamine. The largest single factor favouring the transformation of episodic headache into a chronic one was the drug abuse. The patients studied during 1984 were subjected to detoxification with 6 months' follow-up study. Our investigation suggests that all instant-relief drugs can sustain and possibly initiate a chronic headache.