We know that sleep walking is a genuine disorder. It is a state of combined sleep and wakefulness leaving the sleepwalker is in an attenuated state of consciousness. Those with the disorder can even perform complex tasks behaviors while sleeping such as moving furniture around, cooking, or cleaning. In rare cases, according to the American Alliance for Healthy Sleep and other organizations devoted to sleep studies and education, a sleepwalker may get in his or her car and drive away.
In a 2012 appellate case, a driver who was convicted of driving under the influence of drugsunder Vehicle Code section 23152(a), alleged that he was sleep driving and therefore not criminally liable. The driver who had taken prescription Ambien prior driving his car. He was observed driving erratically. When detained by the police, the driver appeared coherent and was cooperative, but he had glassy eyes, was swaying, and his speech was slow and slurred, but he did not smell of alcohol. The officer concluded that the driver was under the influence of drugs. The blood test results showed that the driver had zolpidem in his system. Zolpidem is marketed under the brand name Ambien. The driver’s blood test results indicated that the driver had taken more than the recommended dosage of the drug. According to both the prosecution and defense experts at trial, sleep driving can be a rare side effect of taking Ambien. Indeed, among the warnings on the Ambien label, is that it can cause sleep driving.
At trial, the driver argued that he acted (drove) while legally unconscious. Unconsciousness can be a complete defense to a criminal charge. (Penal Code §26.) To be legally unconscious does not require that a person be unable to respond or walk, and so on but only that the person is not conscious of acting. For example, someone could perform an unlawful act while suffering from a delirium or after unknowingly ingesting a drug (for example, drinking punch not knowing it is laced with LSD, as happened in an actual California case), or after being taking a prescription drug. But that last example, which would seem to apply here, has a catch. The defense of unconsciousness is only available if it is not induced by voluntary intoxication. (Penal Code §22.) This exception makes sense: someone who decided to get drunk or high should not them be able to use the defense that he or she was not aware. The driver here voluntarily took the Ambien and he had admitted that he knew Ambien can cause sleep driving. Knowing the potential effect is key.