According to Mayo Clinic, depression (also known as major depressive disorder), "is a mood disorder that causes a persistent feeling of sadness and loss of interest."

It's not just feeling down from time to time; it's constant feelings of worthlessness, hopelessness, and anxiety. It's losing interest in activities you usually enjoy. It's being agitated over the smallest occurrences. These are just a few of the things depression does.

Obviously, there are people who have no idea what it's like to struggle with depression. Some simply do not understand it. Some will tell you to "cheer up." Some do not see depression as a big deal.

Unfortunately, there are people who think they know what depression is and what it's all about, despite the fact that they haven't experienced it themselves, and they are not psychologists. I have had the displeasure of interacting with people exactly like this.

I have heard several responses from others when I open up to them about my struggle with depression:

"I don't know what to tell you."

"Just think happy thoughts."

"But your life is going so well."

The worst one I've heard thus far is "You know, I think depression is just a state of mind." For some reason, that comment has struck a very raw nerve inside me. I think it's because the person who said it considers themselves wise and experienced, and mental health, in general, is like a foreign concept to them. At least with the other responses I've received over the years, those individuals were just naive.

For those who think they know all about depression, or simply just don't know what it is, let me help you out.

Depression is a serious mental illness and one of the most common mental illnesses in the country. It is characterized by feelings of intense sadness and loss of interest in necessary activities.

There are several causes of depression. One of them is genetics. Is there depression in your family history? Do your parents have it? Grandparents? This increases the risk.

Another cause is going through a traumatic event, like the loss of a loved one or past experiences with abuse. It's extremely difficult to lose someone close to you, and past abuse can lead to clinical depression.

Certain drugs can cause depression as well. It's important to consider the side effects listed on the bottle. Some people, unfortunately, fall prey to these side effects, and depression is a common one.

Other causes include personal conflicts, major events (divorce, new job, moving, etc.), and hormones.

As you can see, depression is not just a state of mind. It's something that can't disappear after walking in a field of flowers. It's not always something that lasts only for a few days.

It's a struggle. We do not want to be sad all the time, and we want to do things that we enjoy, but it's not that simple. Some of us need counseling and/or medication. It's an everyday battle.

Overall, don't try to brush off something so serious. Don't make little comments about how we're just being overdramatic. Don't act like you know everything about everything. One day you might regret it, especially if depression wins its fight with your loved one.