What Is the Insanity Defense?

The mental capacity of a defendant plays a major role in a criminal case. While many states treat incapacitated individuals the same as mentally competent ones, others consider whether the defendant’s insanity could have led to the crime that took place.

In Washington, if a person faces conviction for a crime and successfully proves that he or she lacked the capacity to understand the criminal act, he or she could be found not guilty by reason of insanity. However, there are several rules and requirements involved when a person chooses to establish this defense.

Understanding the Insanity Defense In Washington

When a criminal suspect claims that he or she lacked the mental capacity to understand or commit a particular crime, a court may find him or her not guilty by reason of insanity. Instead of going to prison, the defendant often goes to a mental health treatment facility and is confined if the facility determines that he or she is a danger to society.

Some states do not explicitly allow defendants to invoke the insanity defense, such as Montana, Idaho, Kansas, and Utah. States with insanity defense laws have different requirements for proving this argument. 

Washington follows the M’Naghten rule when assessing a defendant’s insanity defense. Under this rule, the defendant must prove that he or she was unable to distinguish between right and wrong or failed to understand the criminal act. This lack of understanding must be the result of a disease of the mind. 

Washington Laws on the Insanity Defense

If a person chooses to invoke the insanity defense while facing criminal charges in Washington, he or she will need to comply with the requirements established by RCW 10.77030. Under this law, the defendant must file a written notice of his or her intent to rely on the insanity defense at the time of his or her arraignment or within 10 days following the arraignment.

In Washington, a defendant must prove insanity by a preponderance of the evidence. Additionally, the state does not accept the insanity defense if the mental condition was caused by the criminal act for which the defendant is being charged. 

According to RCW 9A.12.010, a defendant must prove the following facts in order to establish the insanity defense.

• At the time of the crime, the mind of the defendant was affected by a mental disease or defect.
• The mental disease or defect affected the mind of the defendant to such an extent that he or she was either unable to perceive the nature and quality of the criminal act, or he or she was unable to determine right from wrong in regard to the criminal act.
• The defense of insanity is established by a preponderance of the evidence. This means that, based on available evidence, the jury finds that there is a greater than 50% chance that the insanity claim is true.

Speak to a Washington Criminal Defense Lawyer

If you or a loved one are facing criminal charges and believe that insanity played a role in your case, speak to a Washington criminal defense lawyer. An attorney can evaluate your case and help you understand whether you qualify for this defense. Your lawyer can also gather the evidence necessary to prove the insanity defense and secure your best possible outcome. Contact a Washington criminal defense lawyer as soon as possible to discuss your legal options.