How To Define Depression

Updated December 14, 2018

Reviewer Laura Angers

Lately, you haven't been enjoying your job. Even though you used to love it, you've been having problems with your boss and some of your coworkers. You dread going to work every day. Sometimes you don't even want to get out of bed in the morning.


Could This Be Depression?

In another scenario, a friend lost her spouse over a year ago. Even with the passage of time, she still keeps going over and over the sad event. She no longer seems interested in going out or having fun. You're not sure if this is just a normal part of grief…or if it's depression.

We've come a long way over the years in understanding this mysterious disorder. We used to have all kinds of names for it: melancholy, a decline, a nervous breakdown. But even though we now understand that it's a real illness with long-ranging consequences, there are still many things we don't understand about depression. What is it? How is it different from sadness or grief? And what might these differences mean when figuring out a plan for treatment?

Here we'll zero in on a workable definition of depression, as well as figuring out its link to other illnesses and disorders.

Symptoms Of Depression

Like any mental illness, depression is defined by a group of specific symptoms.

According to the DSM-5 (a comprehensive manual for diagnosing mental disorders), depression is indicated if you experience any five of these symptoms continuously for over two weeks.

  • A sad mood
  • Loss of interest in activities that you once enjoyed
  • Feelings of fatigue and low energy almost every day
  • Changes in weight/appetite (not eating enough or eating all the time)
  • Either not sleeping at all, or sleeping too much every day
  • Problems with memory, concentration, and decision-making
  • Feelings of guilt and worthlessness
  • Restless, agitated movements (like pacing)
  • Slowed speech and movements
  • Thoughts of death or suicide, or a suicide attempt

It's important to note that these symptoms must be present for an extended period to indicate depression. It's normal to experience some of these symptoms about a sad event, like job loss or the death of a family member. It's when these symptoms last for weeks at a time with no change and no relief that it moves out of the realm of sadness into something more serious.

These symptoms can also be caused by a physical illness, such as a thyroid problem or a vitamin deficiency. These other causes need to be ruled out before depression can be diagnosed.


It's also very common for depression to have physical symptoms. Here are some common ways in which depression might be affecting your body.

  • Headaches
  • Back pain
  • Digestive problems (queasiness, nausea, diarrhea, constipation)
  • Joint pain
  • Insomnia
  • Muscle aches
  • Joint pain
  • Chest pain

Depression can affect your body because it alters the way that your brain registers physical pain. For that reason, if you have any chronic pain, depression may cause it to get worse. If you are prone to migraine headaches, you may find that these become even more of an issue.

Connections Between Depression And Grief

If you have suffered a loss or experienced a traumatic event, you may exhibit many of the symptoms of depression. But although depression and grief are closely related, there are some important differences between them.

Like depression, the symptoms of grief include a sad mood, changes in appetite, poor concentration and focus, and trouble sleeping.

However, after a certain amount of time (different for each person), these symptoms will gradually become less intense.

In contrast, depression sinks its teeth into you for the long term. Though you may have good and bad days, overall your symptoms do not get any better with the passage of time.

Depression also has some symptoms of its own. Feelings of worthlessness and extreme guilt are some of the defining symptoms of the major depressive disorder. These symptoms are not present in uncomplicated grief. And unlike grief, depression can lead to suicide if it isn't treated.

Another way in which grief is different from depression is that it is still possible to have happy thoughts and warm feelings evoked by memories of a lost loved one. But depression carries with it only dark and negative thoughts. If you are severely depressed, it may be almost impossible to entertain any thoughts that are positive or happy.

However, there are times when grief and depression seem to overlap. If the loss was especially traumatic, or if you are prone to depression in the first place, grief can linger on indefinitely, never seeming to lift. This is sometimes referred to as "complicated grief." When this happens, grief evolves into a major depression and may need to be treated as such.

Different Kinds Of Depression

While there are some clearly defining factors of a depressive episode, depression itself can take many forms. This can make a clear definition of this illness even more difficult. It's helpful to break it down into the various kinds of depression that someone might experience.


Major Depressive Disorder

This is the type of depression that we might talk about if we are trying to define clinical depression. It is the classic textbook depression that most of us automatically think of when we use or hear the term.

Your doctor might diagnose you with the major depressive disorder if you've experienced five of the classic symptoms of depression for two weeks or longer.

Persistent Depressive Disorder

If you think that feeling depressed for two weeks is bad…try two years.

This is what happens to people who are diagnosed with the persistent depressive disorder.

Like Eeyore, these people describe themselves as having a sad, dark mood most of the time. They have also experienced two or more of the other symptoms of depression for at least two years.

Premenstrual Dysphoric Disorder

This disorder is diagnosed when women exhibit symptoms of depression every month just before their period.

In addition to the classic symptoms, those with PMDD may have additional symptoms of irritability, mood swings and a poor response to stress.

Bipolar Depression

The symptoms of this disorder also define manic depression. You may be diagnosed with this disorder if you experience extremes of high energy (known as mania) alternating with episodes of classic depression. If you have the symptoms of depression and have also experienced at least one bout of mania, you may be diagnosed with bipolar depression.


Postpartum Depression

If you have just had a baby and are suffering a major depressive episode, you are likely to be diagnosed with postpartum depression.

Seasonal Affective Disorder

This type of depression strikes on a recurring basis every year, usually in the fall or winter. Besides the typical symptoms of depression, you may also find that your energy level decreases dramatically. You can be diagnosed with SAD if you experience symptoms of depression at the same time of the year for two consecutive years.

Psychotic Depression

This illness is diagnosed if you have symptoms of depression accompanied by psychosis. In addition to the symptoms of a depressive episode, you may hear or see things that aren't there. These delusions and hallucinations are psychotic features and require immediate treatment.


With some diseases, it's easy to isolate a clear cause. Not so with depression. The causes are complex and are often a combination of several factors.

Here are a few of the most common causes of depression.


Although we don't yet know the reasons for this, studies have consistently shown that having a parent or sibling that suffers from depression puts you at much greater risk.

A Poor Response To Stressful Events

A dysfunctional reaction to any major life event can send you spiraling into deep depression. A job change, a divorce, your children growing up and moving away, or even the loss of a friendship can be triggered.

Drugs And Medications

Substance abuse has been linked to depression. If you use drugs or alcohol to cope with stress, this is a pattern that may eventually send you into an abyss of hopelessness. But even the use of medications that have been prescribed to you may have depression as a side effect.

Death Of A Loved One

As we've already discussed, the grief following a close friend or family member can become complicated and long-term, leading to a depressive episode.

Physical Illness

We know that our physical and mental health are closely linked. So if you are physically ill, this can directly impact your mental state, too. Also, living with an illness is a stressful circumstance which over time can cause you to become depressed.


With so many elusive factors in defining depression, it's tough to find one clear definition that nails it down. But if you have many of the symptoms for a most of the time for a period of a few weeks, it's a good idea to talk with your doctor or mental health professional about getting the help you need. If you believe you are suffering from depression, remember that help is out there and you deserve to feel better. Don't hesitate to reach out to a therapist at BetterHelp if you need some perspective on these hopeless feelings. Whether it's depression, grief, or something else, there is a light at the end of this long dark tunnel.

Previous Article

Which Natural Supplements Help With Depression?

Next Article

What Are The Stages of Depression?
You Don’t Have To Face Depression Alone. Our Experienced Counselors Can Help.
Get Help & Support With Depression Today
The information on this page is not intended to be a substitution for diagnosis, treatment, or informed professional advice. You should not take any action or avoid taking any action without consulting with a qualified mental health professional. For more information, please read our terms of use.