Three days before the alleged crimes, D's wife told him that she wanted a divorce, and D moved out of their home. In anticipation of eating cake and ice cream at his teenage daughter's afternoon birthday party, D injected himself with a large dosage of insulin. D did not eat anything following this insulin injection. While he and his wife were running errands she noticed that D was 'real quiet' with an 'along-for-the-ride type attitude.' She asked him at least three times during this time frame: 'Are you okay? Do you need something to eat?' He responded, 'No, I'm fine, okay.' When they were exiting a store parking D hit his wife, who was driving the van at the time, on the right side of her head with a hammer. D did not say anything when he hit her. She got out of the van and began running. D met her at the back of the van and tried to shove her into it through the back door. When an owner of a nearby shop came out and talked to D, the wife retrieved her purse from the van and ran away. As she was running D drove past her and turned into a driveway in front of her. After she turned and ran in the opposite direction. Before she could get away, d ran over her with the van and then drove away. She sustained a depressed skull fracture and abrasions and bruises to her entire body. D was charged with attempted first-degree murder, first-degree assault, domestic violence, and two counts of mandatory sentence for violent crimes for allegedly having hit his wife on the head with a hammer and then having run over her with a van. D informed the court that he would be asserting the affirmative defense of involuntary intoxication because he had suffered from hypoglycemia at the time of the alleged crimes. D is an insulin-dependent diabetic. Hypoglycemia occurs when a diabetic injects, or ingests, insulin and then fails to eat properly. D proposed to call an endocrinologist, Dr. Daniel Bessesen, to testify that D's injection of insulin on the morning of the alleged crimes, coupled with a lack of food, resulted in his hypoglycemic condition. D has had prior occasions of hypoglycemia. Dr. Bessesen would testify as to how hypoglycemia, in general, can affect a person. The trial court concluded that Dr. Bessesen would have testified that D's hypoglycemia affected his 'rational thought processes to a degree [so as to] . . . affect the mens rea of D or his ability to form a specific culpable mental state.' P argued that the proposed testimony was tantamount to a 'temporary insanity' defense and thus not permitted under Colorado law. The trial court ruled that, as a matter of law, insulin-induced hypoglycemia could not constitute the affirmative defense of involuntary intoxication. The court also ruled that evidence pertaining to D's hypoglycemia could be presented only if D entered a plea of not guilty by reason of insanity. D objected, arguing that 'Hypoglycemia is not a mental disease or defect. Following D's entry of his plea of not guilty by reason of insanity, the trial court ordered him to undergo a mental health examination. The court-appointed examiner concluded that Garcia had suffered an amnestic disorder due to insulin-induced hypoglycemia at the time of the crimes and that this disorder had caused him to be legally insane. A second expert, Dr. Karen Fukutaki. concluded that D was legally sane at the time of the crimes. D claimed he had no recollection of what had happened and was not legally responsible for his acts because he was insane at the time the acts were committed. The trial court instructed the jury on the defense of insanity. No instruction was requested or given on involuntary intoxication as an affirmative defense. D was convicted of attempted second-degree murder and first-degree assault. The court of appeals held that the trial court erred by not permitting D to proceed under his claimed affirmative defense of involuntary intoxication and reversed and remanded for a new trial. P appealed.