Major Depression
http://www.psychologyinfo.com/depression/major.htm

This is the most severe category of depression. In a major depression, more of the symptoms of depression are present, and they are usually more intense or severe. A major depression can result from a single traumatic event in your life, or may develop slowly as a consequence of numerous personal disappointments and life problems. Some people appear to develop the symptoms of a major depression without any obvious life crisis causing it. Other individuals have had less severe symptoms of depression for a long time (such as Dysthymic disorder), and a life crisis results in increased symptom intensity.

Major depression can occur once, as a result of a significant psychological trauma, respond to treatment, and never occur again within your lifetime. This would be a single episode depression. Some people tend to have recurring depression, with episodes of depression followed by periods of several years without depression, followed by another episode, usually in response to another trauma. This would be a recurrent depression. In general, the treatment is similar, except that treatment usually is over a longer time period for recurrent depression.

Professional debate continues regarding whether some people develop “endogenous depression” without any identified psychological causes. An endogenous depression is a biologically caused depression, due presumably to either genetic causes or a malfunction in the brain chemistry. But, all depression involves some changes in brain chemistry, even when the cause is clearly a psychological trauma. After psychological treatment and recovery from depression, the brain chemistry returns to normal, even without medication. To date, there is no hard research evidence to support the notion of endogenous depression. Sometimes this term is used to describe people who do not respond well to treatment, and sometimes it is a rationale to prescribe medication alone, and not to offer any psychological treatment for the depression. In general, the majority of people who require antidepressant medication for their depression respond to treatment better when psychotherapy, particularly cognitive-behavioral psychotherapy, is provided in addition to the medication.  Medication treats the symptoms of depression, and is often a vital part of the treatment program, but it is essential to treat the psychological problems that caused the depression.

Research has shown that cognitive therapy is the best treatment for depression, as compared to medication and other forms of psychotherapy. However, many people respond better to a combination of medication and cognitive therapy. It does not make sense to only prescribe medication, without offering psychotherapy as well, because of the added benefits shown in research studies. There are some people who respond positively to psychotherapy, but plateau at a mild level of depression, without complete recovery from all of the symptoms. Often, these individuals are maintained on antidepressant medication after they have completed psychological treatment. Remember, only physicians are qualified to prescribe medication. Your psychologist will refer you to your primary care physician, or to a psychiatrist, for a medication evaluation, if it appears to be indicated.

Symptoms of Depression
A Major Depression is marked by a combination of symptoms that occur together, and last for at least two weeks without significant improvement.  Symptoms from at least five of the following categories must be present for a major depression, although even a few of the symptom clusters are indicators of a depression, but perhaps not a major depression.

Persistent depressed, sad, anxious, or empty mood
Feeling worthless, helpless, or experiencing excessive or inappropriate guilt
Hopeless about the future, excessive pessimistic feelings
Loss of interest and pleasure in your usual activities
Decreased energy and chronic fatigue
Loss of memory, difficulty making decisions or concentrating
Irritability or restlessness or agitation
Sleep disturbances, either difficulty sleeping, or sleeping too much
Loss of appetite and interest in food, or overeating, with weight gain
Recurring thoughts of death, or suicidal thoughts or actions
This list is a guide to help you understand depression. It is not offered for you to diagnose yourself. If you have some of these symptoms, don’t focus on how many symptoms you have. Instead, talk to a psychologist about how you have been feeling, to see if he/she can help.

First Person Description of Major Depression
It takes the greatest effort to get out of bed in the morning.
I am tired all day, yet when night comes, sleep evades me.
I stare at the ceiling, wondering what has happened to my
life, and what will become of me. Nothing is getting done
at work. I have projects to complete, but I can’t think. I try
to focus on my work, and I get lost. I keep wondering when
the boss will discover how little I have accomplished. My wife
does not understand. She keeps telling me to “snap out of it.”
I’m irritable all the time, and yell at the kids, then I feel
terrible later. Nothing is fun any more. I can’t read, and the
music I used to enjoy so much does nothing for me. I am bored,
but I feel like doing nothing. There are times, when I’m alone,
that I think that life is hopeless and meaningless, and I can’t
go on much longer.

Sleep problems, difficulty with concentration, chronic fatigue, irritability, feelings of hopelessness, loss of interest in pleasurable activities – the list of symptoms does not convey the despair of depression. When you feel lost, hopeless, and don’t know what to do, you might be depressed. Even if you have just a few of the symptoms of depression, talk to someone who can help, consult with a psychologist, and find out what can be done to help you change!
Differences Between Major Depression and Other Depressions
The differences between Major Depression and other depressions, such as bipolar depression, dysthymia, or reactive depression, are primarily intended for psychologists planning treatment, and are of less concern to the average person. When you review the list of symptoms for major depression, and you have four symptom clusters, instead of five, you should not ignore it or forget about it. There is no diagnosis of Moderate Depression, other than to call it “unspecified.” Instead, ask yourself this question: “Does the depression interfere with my life, my relationships, my productivity or my happiness?” If the answer is yes, then don’t wait, talk to a psychologist soon.

Reactive depression is called an Adjustment Disorder with depressed mood.  This means that something traumatic occurred in your life, such as a relationship breakup, or loss of a job, and you became mildly to moderately depressed as a result.  Psychological treatment can definitely help you to feel better, and will help you get your life back on track sooner, rather than later, but you can still manage okay. If a life crisis occurs and you develop symptoms of a major depression, then it is a major depression, even if it is also a reactive depression.

Dysthymic disorder is a chronic, low level depression, that continues for years. Occasionally, individuals with dysthymia also experience a major depression, when a life crisis occurs. If you are depressed all the time, even if only mildly depressed, you should consult with a psychologist. You don’t have to live your life in depression. Often, a person has been mildly depressed for years, and a crisis occurs, and he/she finally consults a psychologist. In such a case, the treatment will probably take longer, because of the chronic depression underneath the major depression.

Depression, not otherwise specified, is a category used by psychologists when the symptoms do not fit neatly into one of the other categories. For example, a person has been mildly depressed for a long time, but not long enough to diagnose dysthymia. The specific pattern of symptoms and duration of symptoms will determine the proper psychological treatment.