Lately Lindsay hasn't felt like herself. Her friends have noticed it. Kia was surprised when Lindsay stayed home instead of joining their usual Saturday group at the mall. She spent most of the day sleeping.

Staying in more than usual isn't the only change in Lindsay. She's always been a really good student, but over the past couple of months her grades have fallen. She has trouble concentrating. She forgot to turn in a paper and is having a hard time getting motivated to study.

Lindsay feels tired all the time but has difficulty falling asleep. She's gained weight too. When her mother asks her what's wrong, Lindsay just feels like crying. But she doesn't know why. Nothing particularly bad has happened. Yet Lindsay feels sad all the time and can't shake it.

Lindsay may not realize it yet, but she is depressed.

Regular Sadness vs. Depression

Feeling sad, down, or discouraged are natural human emotions. They're reactions to the hassles and hurdles of life. We all feel this way at times.

We may feel sad over an argument with a friend, a breakup, or a best friend moving out of town. We might be disappointed about doing poorly on a test. Or perhaps we feel discouraged if our team can't seem to break its losing streak. The death of someone close can lead to a specific kind of sadness — grief.

Most of the time, people manage to deal with these feelings and get past them with a little time and care.

Depression is more than occasionally feeling blue, sad, or down in the dumps, though. Depression is a strong mood involving sadness, discouragement, despair, or hopelessness that lasts for weeks, months, or even longer.

Depression affects more than a person's mood. It drains the energy, motivation, and concentration a person needs for normal activities. It interferes with the ability to notice or enjoy the good things in life.

Signs of Depression

When people have depression, it affects their emotions and mood. It twists their way of thinking. Depression can also affect people physically, even causing body aches and pains. Not everyone who is depressed shows it in exactly the same way, though.

Here are some of the things people notice with depression:

• Negative feelings and mood. Depression involves feeling a negative, low mood for weeks or more. Someone with depression might feel unusually sad, discouraged, or defeated. He or she may feel hopeless, helpless, or alone. Some people feel guilty, unworthy, rejected, or unloved. Any or all of these emotions can be part of a depressed mood.
  
  Depression doesn't always cause people to feel mostly sad, though. For some people, depression shows up as a lasting mood of feeling irritable, easily annoyed, angry, or alienated.
  
• Negative thinking. When somebody has depression, it can cloud everything. The world looks bleak, and the person's thoughts reflect that hopelessness and helplessness. This can make a person think things will never get better, that problems are too big to solve, that nothing can improve the situation, or that nothing matters.
  
  People with depression tend to have negative and self-critical thoughts. They may believe they are worthless and unlovable — even though that's not true. Depression can cause someone to think that life isn't worth living. That can lead people with depression to think about harming themselves or about ending their own life.
• Low energy and motivation. People with depression may feel tired, drained, or exhausted. They might even move more slowly or take longer to do things. It can feel as if everything requires more effort. People who feel this way might have trouble motivating themselves to do or care about anything.
• Concentration. Depression can make it hard to concentrate and focus. It might be hard to complete schoolwork, pay attention in class, remember lessons, or stay focused on what others say.
• Physical symptoms. People can feel depression in their bodies as well as their minds. Some people have an upset stomach or loss of appetite. Some might gain or lose weight. Some people notice headaches and sleeping problems when they're depressed.
• Social withdrawing. Because of feelings of sadness and low energy, people with depression may pull away from friends and family or from activities they once enjoyed. This usually makes them feel more lonely and isolated. That can make the depression and negative thinking worse.

Depression Can Go Unrecognized

People with depression may not realize they are depressed. Because self-critical thinking is part of depression, some people might mistakenly think of themselves as a failure, a bad student, a quitter, a slacker, a loser, or a bad person.

Because depression might affect how a person acts, it can be misunderstood as a bad attitude. Other people may think the person isn't trying or not putting in any effort. For example, a negative or irritable mood can cause someone to act more argumentative, disagreeable, or angry. That can make the person seem difficult to get along with or cause others to keep their distance. Low motivation, low energy, difficulty concentrating, and thoughts of "why bother?" can lead someone to skip classes or school.

Some people with depression have other problems as well. These can intensify feelings of worthlessness or inner pain. For example, people who cut themselves or who have eating disorders or who go through extreme mood changes may have unrecognized depression.

When depression is recognized and treated, it often clears the way for other problems to get treated, too.

Why Do People Get Depressed?

There is no single cause for depression. Many things play a role, including inherited traits from family members who may have had depression, or living in a difficult family or social environment.

Depression can happen in reaction to difficult or stressful life events. Whether a person tends to be optimistic or pessimistic can play a role in depression, too.

Depression involves the balance of naturally occurring chemicals in the brain. These chemicals, called neurotransmitters, affect mood.

Many things can affect the brain's production of neurotransmitters — including daylight and seasons, a challenging social environment, life events, and certain medical conditions.

Sometimes a person can figure out how some of these factors may have contributed to feeling depressed. For example, in winter, when there's less light, some people have a tendency to a kind of depression called seasonal affective disorder (SAD).

Other times, a person can become depressed for no obvious reason. Not knowing what caused someone's depression doesn't make it less real, though.

What Helps Depression Get Better?

Depression can get better with the right attention and care — sometimes more easily than a person thinks.

But if it's not treated, things can stay bad or get worse. That's why people who are depressed shouldn't wait and hope it will go away on its own.

Friends or others need to step in if someone seems severely depressed and isn't getting help. The right help can mean doing all of these things:

Get a Medical Checkup

A doctor can check for any health conditions that might be causing symptoms of depression. For example, conditions such as hypothyroidism can cause a depressed mood, low energy, and tiredness. Mono can make a person feel tired and depressed.

Finding out if another health condition is causing sadness or other symptoms that seem like depression can help someone get the right treatment.

Talk to a Counselor

In addition to a checkup with a doctor, it helps to meet with a mental health professional. A psychologist, psychiatrist, or other therapist can evaluate and diagnose depression and create a plan to treat it.

If someone has depression, talk therapy with a therapist or counselor is very effective in treating it. Here are some of the ways therapy can help with depression:

• A therapist can help people with depression understand their emotions, put feelings into words, and feel understood and supported.
• Therapy can help people work out problems as well as identify and overcome negative thinking patterns that are part of depression.
• Therapists can help people develop more positive ways of looking at things, increase self-esteem, and become more accepting of themselves.
• Therapists can help people build the confidence to deal with life's struggles.

Treatment for depression might include talk therapy, medication, or a combination of both. Sometimes, therapists might recommend daily exercise, exposure to daylight, or better ways of eating. A therapist might teach relaxation skills to help someone get a good night's sleep. All of these things can affect the brain's production of neurotransmitters.

What Helps Depression Get Better?

Get Support

Many people find that it helps to open up to parents or other adults they trust. Simply saying something like "I've been feeling really down lately and I think I'm depressed" can be a good way to begin the discussion.

If you think you might be depressed, ask your parent to arrange an appointment with a therapist. If a parent or family member can't help, turn to your school counselor, school nurse, or a helpline to get help.

Friends and people who care about you can support you in other ways, too:

• They can listen and talk, showing that they understand what you're feeling.
• They can remind you that things can get better, and that they are there for you through the downs and ups.
• They can help you see the things that are already good about your life, even when it's hard for you to notice.
• They can keep you company and do enjoyable or relaxing things with you.
• They can give you honest compliments and help you find things to laugh or smile about.

Help Yourself

In addition to getting help from a professional therapist and support from friends and family, people with depression can do other things to help themselves.

Some simple things can have a powerful effect on mood. They include daily exercise, eating healthy foods, and getting the right amount of sleep.

Focusing on positive emotions and being with positive people can help, too. Do yoga, dance, and find creative self-expression through art, music, or journaling. Daily exercise, meditation, daylight, and positive emotions all can affect the brain's activity in ways that restore mood and well-being.

Depression can be effectively treated if you take the right steps:

• Don't wait for it to just go away.
• Do get evaluation and care.
• Do what you can to care for yourself.

Reviewed by: D'Arcy Lyness, PhD
Date reviewed: November 2011