The Insanity Defense: Definition, Famous Cases, Pros & Cons

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Acquiescence in Law: Definition & Concept

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:04 What is the Insanity Defense?
  • 0:31 Insanity Defense Cases
  • 2:01 Insanity Defense Pros
  • 2:29 Insanity Defense Cons
  • 3:23 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed
Lesson Transcript
Instructor: Jessica Schubert

Jessica is a practicing attorney and has taught law and has a J.D. and LL.M.

This lesson will review the insanity defense. You will first examine the definition of the insanity defense. Then you will look at several famous insanity defense cases. Finally, you will review the pros and cons of the insanity defense.

What Is the Insanity Defense?

You may either recall or have at least read about President Reagan getting shot back in the 1980s. The man who attempted the assassination tried to assert the insanity defense when he was on trial for the crime.

The insanity defense is a defense where the individual who is charged with a crime admits that they committed a crime, but claim that they are not responsible for the crime due to mental illness; in other words, they are not guilty by reason of insanity.

Insanity Defense Cases

The initial case establishing the legal insanity test is commonly referred to as the M'Naghten case. In this case, the British Prime Minister was shot and killed. The shooter claimed that he believed that the Prime Minister was in a conspiracy against him and he was defending himself. The court decided to acquit, or dismiss, the charges against the shooter, by reason of insanity. However, the shooter was then sent to a mental institution for the rest of his life. The standard created by this case, which was that there was a presumption of sanity unless one could show a defect of the mind which resulted in one's inability to comprehend the nature of the act as wrong, became the standard in the United States.

Let's return to our earlier example that opened this lesson. This was a famous case that utilized the insanity defense. It was the case involving the assassination attempt of former President Ronald Reagan. The shooter in that case, John Hinckley, apparently believed that he was part of the film Taxi Driver. He believed that President Reagan was part of the movie and that Hinckley, as the main character, had to stalk the President and engage in a shoot out with him. Hinckley then did just that, shooting then President Reagan several times. When on trial, Hinckley's attorneys used the insanity defense to defend Hinckley's actions, also citing his fixation with Jody Foster, one of the actors in the film. Moreover, the Hinckley's defense attorneys demonstrated that Hinckley had had schizophrenia for years and submitted documentation of the disease. Hinckley was successful in the use of the insanity defense.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account