But stress can lead to -- or be a sign of -- more serious mental disorders, like depression.

Depression: a mood disorder

Yes, that is true. Merriam Webster defines depression as “low in spirits.” Other dictionaries describe it as a feeling of sadness.

Depression can be a short-term reaction to something bad that happens. But it can also be long term condition.

U.S. mental health officials define it as “a serious mood disorder that affects how you feel, think, and handle daily activities, like sleeping, eating, or working.”

Mood. That is a good word for us to talk about. Your mood is an emotional state. If you are enjoying a walk in a pretty park on a warm, sunny day, you are probably in a good mood.

If you are watching a sad movie, it might bring your mood down. If you are stuck in traffic, you might get in a really bad mood.

Anxiety and phobias

Yes, bad traffic can cause anxiety, especially if you are trying to get somewhere at a certain time. Anxiety is a state of worry and unease. The adjectival form is anxious. For example, "I am anxious I will be late for the wedding."

Do you get anxious when you are flying on a plane?

Oh yes, flying can cause stress for a lot of people, including me. Some suffer from a fear of flying. The medical term for that is aviophobia.

A phobia is an extreme or unreasonable fear or dislike of something. A couple common conditions are acrophobia, which is a fear of heights; and claustrophobia, a fear of small spaces.

And a few years back there was a horror movie called Arachnophobia.

That was about an invasion of deadly spiders. That is my phobia! I am terrified of spiders! I actually had a panic attack watching that movie.

I’ve never had one before. What is it like? What does it mean?

Panic attack

Well, panic is sudden, uncontrollable fear or anxiety. It can cause wild, sort of, unthinking behavior. A panic attack is a period of extreme anxiety. It might even become hard for a person to breathe. Which is what happened when I watched Arachnophobia.

People who have phobias or other disorders often seek mental health therapy. Therapy is a term that can be used for any kind of continuous medical treatment. People might go to physical therapy after a knee operation, for example.

But when people just say therapy alone, they often mean mental health or psychotherapy. Another word for such therapy is counseling.

Counseling or therapy can come in all kinds of settings. You can meet with a group of people that share a common problem, or you can have private visits with a doctor called a psychiatrist. You might also have a longer-term stay at a medical center.

Rehab

Yeah, like when movie stars check themselves into rehab. Rehab stands for rehabilitation. To rehabilitate means to restore to a healthy condition. There are many rehab centers in the U.S. that treat drug addiction, for example.

That's another term worth explaining, Bryan, drug addiction. This means a dangerous, unhealthy dependence on a drug or drugs. This can include alcohol. Although, a dependence on alcohol is often called alcoholism.

I think I might be addicted to caffeine. I cannot do much of anything before I have my morning coffee. This addiction does not seem to cause me real problems, though. But, I do get a bad mood if I don’t have coffee!