In People v. Mion, the Colorado Supreme Court considered whether a defendant may assert the affirmative defense of involuntary intoxication when he knowingly consumed an intoxicating product but claimed an unknown additional substance caused his loss of control
Isaac Mion was convicted of aggravated robbery, menacing and criminal mischief stemming from erratic behavior following his decision to smoke a joint he received from an acquaintance. Mion argued he was involuntarily intoxicated because the joint allegedly contained an unknown intoxicant beyond marijuana.
The Supreme Court reversed the Court of Appeals and held that for purposes of Colorado’s involuntary intoxication statute, the relevant “substance” is the entire product consumed, not each individual intoxicant. Because Mion knowingly smoked a joint and knew or should have known it had intoxicating effects, his intoxication was deemed self-induced as a matter of law, barring the defense. The Court emphasized this interpretation preserves the statute’s “ought to know” reasonableness standard and prevents defendants from avoiding responsibility by speculating about unknown ingredients.
The decision limits the availability of the involuntary intoxication defense in Colorado, particularly in cases involving drugs or products that may contain multiple intoxicants. By focusing on the product consumed rather than its components, the ruling reinforces criminal accountability where defendants voluntarily ingest substances with foreseeable intoxicating effects and provides clearer guidance to trial courts evaluating requests for involuntary intoxication jury instructions.
Read the full published opinion at coloradojudicial.gov/system/files/opinions-2026-01/24SC2.pdf.