Oregon Revised Statutes Crimes and Punishments § 161.125

(1) The use of drugs or controlled substances, dependence on drugs or controlled substances or voluntary intoxication shall not, as such, constitute a defense to a criminal charge, but in any prosecution for an offense, evidence that the defendant used drugs or controlled substances, or was dependent on drugs or controlled substances, or was intoxicated may be offered by the defendant whenever it is relevant to negative an element of the crime charged.

(2) When recklessness establishes an element of the offense, if the defendant, due to the use of drugs or controlled substances, dependence on drugs or controlled substances or voluntary intoxication, is unaware of a risk of which the defendant would have been aware had the defendant been not intoxicated, not using drugs or controlled substances, or not dependent on drugs or controlled substances, such unawareness is immaterial.