What Are Cognitive Disorders? - Definition and Perspectives

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: What Is Delirium? - Definition, Causes & Treatment

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

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:06 Cognitive Disorders
  • 1:31 Dementia
  • 2:22 Delirium
  • 3:27 Amnesia
  • 4:50 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

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Natalie Boyd

Natalie is a teacher and holds an MA in English Education and is in progress on her PhD in psychology.

The human ability to think is what sets us apart from the other animals. But what happens when memories or the ability to learn disappears? In this lesson we'll look at three common types of cognitive disorders: dementia, delirium, and amnestic disorders.

Cognitive Disorders

Josie has lived in the same house for almost 50 years. She bought it when she and her late husband first got married, and she raised her children there. Recently, her family has noticed a problem when they come to visit her. She doesn't always remember who they are. Often, she talks to her daughter as though she was her sister, and sometimes she calls her granddaughter by her daughter's name.

Mitchell has always been a healthy, happy man. He's in the prime of his life and everything is going well for him. But last month, he contracted pneumonia and ended up in the hospital. Shortly after going back home, Mitchell woke up one day feeling disoriented and confused. He wasn't sure where he was or what he was supposed to do.

Maxine, meanwhile, was in a car wreck and had to have brain surgery. After she woke up, she couldn't remember anything from before the accident. She can still make new memories, and she still remembers how to tie her shoe and who the president is, but she can't remember going to school or meeting her husband.

Josie, Mitchell, and Maxine are all suffering from different types of cognitive disorders. Cognitive disorders occur when a person experiences a loss or interruption of normal thought processes. There are three general types of cognitive disorders: dementia, delirium, and amnesia. Let's look closer at each one.


Dementia occurs when a person loses cognitive ability, including memory, thought, language, problem solving, and judgment. The word 'dementia' comes from the Latin words for 'without mind.' And that's essentially what it is: A person with dementia is operating with only part of their mind.

Remember Josie? She's starting to lose her memories of her daughter growing up and her granddaughter being born. This is one sign of dementia. She also sometimes has a really hard time expressing herself, and she can't do the crossword puzzles she used to love. Both of these are also signs of dementia. Dementia is often associated with brain diseases like Alzheimer's or Parkinson's disease, but dementia can also be caused by other things, including head trauma, or drug and alcohol abuse.


Delirium happens when a person becomes disoriented and confused. Because it has similar symptoms, delirium is sometimes confused with dementia. But delirium usually has a faster onset. It can happen suddenly, whereas dementia usually grows over months or years.

Mitchell had pneumonia and then woke up one day completely confused. He didn't know where he was, even though he was in his own home. Confusion is a key sign of delirium. Oftentimes, patients are either very agitated or they are unusually calm. For example, if Mitchell woke up in a panic, shouting and trying to get out of his house, he would be displaying the agitation often associated with delirium.

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