The Mental Treatment Act (1945) is currently undergoing review to enable Ireland to meet it's international obligations. The Green Paper on Mental Health (1992) makes a number of suggestions regarding this. One such is the deletion of Addiction as sufficient grounds for involuntary admission to a psychiatric hospital or unit. This study looked at the possible impact such a proposal might have on the doctor's clinical choice in the management of addiction. The casenotes and temporary certificates of 191 involuntary admissions to St. Brendan's Hospital were examined. 9 cases (4.7%) were admitted for the direct effect of addiction, i.e., intoxication or uncomplicated withdrawal. The conclusion of this study is that the deletion of the addiction criterion from future mental health legislation would, in itself, have little impact on the number of committals. This is because the majority of those with evidence of Substance Abuse have a concurrent disorder that would be covered by the remaining criteria.