We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is the Mental Disorder Defense?

By M. Lupica
Updated May 17, 2024
Our promise to you
WiseGeek is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At WiseGeek, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

In order to be convicted of most crimes, it needs to be found that the actor had the appropriate mens rea — that is, the “state of mind” — to commit the crime. The state of mind required depends on both the crime and the jurisdiction, but certain mental defects may negate the existence of that particular state of mind. There are two broad categories of mental disorder defense that are typically asserted. First is the insanity defense that depends on a particular defect of the defendant’s mind. The other category of mental disorder defense is intoxication, which may be broken down into voluntary and involuntary intoxication.

In order to assert a mental disorder defense, the defendant must show that there was a defect of some kind that prevented him or her from forming the necessary state of mind to commit the crime. For example, most jurisdictions require that anyone convicted of murder must have had “malice aforethought” in committing their actions that led to the death of the victim. Malice aforethought generally implies that the person had specifically intended to cause at least serious bodily harm to the victim before committing the act that killed him or her. An appropriate mental disorder defense would tend to show that the defendant did not have the mental capability to intend to kill or seriously harm the victim at the time of the offending action. If this mental disorder defense is successful, it would not necessarily result in the innocence of the defendant, but may have the crime reduced to a less serious charge such as manslaughter.

There are several types of tests for the insanity mental disorder defense that are recognized in various jurisdictions. However, there are two in particular that are most commonly recognized. The majority rule is the “M’Naghten” rule, which may be asserted if the defendant did not know his or her act would be wrong or did not understand the nature and quality of his or her actions. The other is the “irresistible impulse” rule, which requires a showing that the defendant was unable to control his or her actions or conform his or her conduct to the law.

Intoxication may be raised as a mental disorder defense if the intoxication would have put the defendant in a state in which he or she could not form the requisite intent to committing the particular crime for which he or she is charged. The one line to be drawn is if the intoxication was voluntary or involuntary. Involuntary intoxication occurs when a person ingests an intoxicating substance without knowledge of its nature, under threat of serious bodily harm or pursuant to medical advice. Conversely, voluntary intoxication occurs when a person purposefully takes an intoxicating substance with the knowledge of its intoxicating nature and is a much

WiseGeek is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.