Facts
- Raymond Quick, a diabetic nurse at a mental health facility, assaulted a patient.
- Quick claimed he acted during a hypoglycemic episode resulting from taking insulin but failing to eat enough.
- At trial, the judge directed the jury to consider insanity, leading to a special verdict of "not guilty by reason of insanity."
- Quick appealed, contending that his actions were caused by external factors (insulin administration and lack of food), not a "disease of the mind."
Issues
- Whether hypoglycemia induced by insulin and lack of food constitutes an external factor or a "disease of the mind" for the purposes of criminal law defences.
- Whether the trial judge was correct in instructing the jury to consider insanity rather than automatism as the applicable defence.
Decision
- The Court of Appeal held that Quick’s hypoglycemic state was caused by an external factor—insulin and lack of food—comparable to effects from head injuries or anesthesia.
- The court determined that the appropriate defence in such circumstances was automatism, not insanity.
- The judge’s direction to the jury to treat the episode as insanity was incorrect.
Legal Principles
- "Disease of the mind" encompasses conditions affecting mental function, whether physical or psychological, but excludes states caused solely by external agents such as drugs, alcohol, or physical harm, unless revealing a pre-existing internal condition.
- Automatism caused by external factors removes the actus reus and leads to a full acquittal.
- Automatism with an internal cause classified as "disease of the mind" results in a special insanity verdict.
- The defendant bears the initial burden to present sufficient evidence supporting a claim of automatism, usually requiring medical evaluation to determine the cause.
Conclusion
Quick v Prettejohn clarified the distinction between automatism resulting from external factors and that linked to a "disease of the mind." The decision established that automatism from an external cause supports a complete defence, while internal causes invoke insanity, shaping subsequent case law on mental capacity and criminal responsibility.