It is a defense that the person who engaged in the prohibited conduct did so while he was intoxicated, only if the intoxication resulted from the introduction of a substance into his body:

1. (1) without his consent; or

2. (2) when he did not know that the substance might cause intoxication.

   As added by Acts 1976, P.L.148, SEC.1. Amended by Acts 1977, P.L.340, SEC.10; Acts 1980, P.L.205, SEC.1; P.L.210-1997, SEC.4.