Depressive Disorders: Definition, Types, Causes & Treatment

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Dysthymia and Cyclothymia: Definition, Symptoms & 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 Depressive Disorders
  • 1:09 Diagnosis
  • 4:17 Causes & Treatment
  • 5:43 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 Audio mode
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.

What is depression? In this lesson, we'll look closer at depressive disorders, including the diagnostic criteria, causes, and treatments of major depressive disorder.

Depressive Disorders

Laurie is blue. She's recently broken up with her boyfriend, she's failing her statistics class, and she's really worried she might get kicked out of school. She feels sad all the time, and isn't interested in hanging out with her friends, and is always tired despite sleeping most of the day. Not only that, she's lost her appetite and is having trouble concentrating in school.

Laurie might be suffering from a depressive disorder, a mood disorder that involves feeling sad and losing interest in things that are normally interesting to the person. There is more than one type of depressive disorder. Major depressive disorder is what most people think of when they think of depression. It involves long periods of severe sadness or loss of interest and other symptoms as well.

But there's another type of depressive episode, called dysthymia, which is a less severe form of major depressive disorder. Dysthymia is chronic (that is, it lasts a long time), but the symptoms are not as severe.


So which one does Laurie have? Imagine that you're her psychologist. It's your job to figure out if Laurie has major depressive disorder or dysthymia. In order to figure that out, you consult a book called the Diagnostic and Statistical Manual of Mental Disorders, or DSM for short. This book lists the criteria required to be diagnosed with a psychological disorder. To check if Laurie has major depressive disorder, you turn to the page with the diagnostic criteria for that disorder and you compare her symptoms to those in the book.

1. Depressed mood and/or loss of interest in pleasurable things.

Laurie is feeling sad and she doesn't want to hang out with her friends, so she has both of these symptoms and meets this criterion.

2. At least 3 or 4 other symptoms.

A patient needs a total of five symptoms, including depressed mood and/or loss of interest in pleasurable things. Other possible symptoms include changes in appetite, sleeping too much or having insomnia, movement issues, fatigue, feelings of worthlessness or guilt, trouble concentrating, or thinking and recurrent thoughts of death or suicide.

Remember that Laurie has both depressed mood and loss of interest in pleasurable things. She needs to display at least three other symptoms in order to have a total of five symptoms. She's tired all the time, sleeps much more than usual, has lost her appetite and is having trouble concentrating. Since she has a total of six symptoms, she meets this criterion.

3. The symptoms have been present almost every day for at least two weeks.

Laurie's been feeling this way for a while, so we can check this one off.

4. There are no manic episodes.

Sometimes, depression is mirrored with manic episodes, when the patient feels energized, ambitious and on top of the world. If that's the case, the patient is not diagnosed with major depressive disorder. But Laurie only has depressive symptoms, so she meets this criterion.

5. The symptoms cause distress or impairment.

Laurie is having trouble in school and doesn't like feeling this way. Because she is impaired at school and experiencing distress, we can check this one off.

6. The symptoms cannot be explained by a physical illness or by bereavement.

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