According to the National Institute of Mental Health, major depressive disorder is characterized by a combination of symptoms that interfere with a person's ability to work, sleep, study, eat, and enjoy once-pleasurable activities.
There are times you may feel sad, lonely, or hopeless for a few days. But major depression -- clinical depression -- lasts longer and is disabling. It can prevent you from functioning normally. An episode of clinical depression may occur only once in a person's lifetime. More often, though, it recurs throughout a person's life.
In addition, with major depression, one of the symptoms must be either depressed mood or loss of interest. The symptoms should be present daily or for most of the day or nearly daily for at least two weeks. Also, the depressive symptoms must cause clinically significant distress or impairment in functioning. The symptoms cannot be due to the direct effects of a substance -- drug abuse, medications -- or a medical condition, such as hypothyroidism, nor occur within two months of the loss of a loved one.
For in-depth information, see WebMD's Major Depression.
Chronic depression, or dysthymia, is characterized by a long-term (two years or more) depressed mood. There are also symptoms present that are associated with major depression but not enough for a diagnosis of major depression. Chronic depression is less severe than major depression and typically does not disable the person. If you have dysthymia or chronic depression, you may also experience one or more episodes of major depression during your lifetime.
For in-depth information, see WebMD's Chronic Depression (Dysthymia).
The key symptoms of atypical depression include:
Regular -- or "typical" -- depression, on the other hand, tends to be marked by pervasive sadness and a pattern of loss of appetite and difficulty fall or staying asleep.
For in-depth information, see WebMD's Atypical Depression.
Bipolar disorder -- sometimes referred to as manic depression -- is a complex mood disorder that alternates between periods of clinical depression and times of extreme elation or mania. There are two subtypes of bipolar disorder: bipolar I and bipolar II.
With bipolar I disorder, patients have a history of at least one manic episode with or without major depressive episodes.
With bipolar II disorder, patients have a history of at least one episode of major depression and at least one hypomanic (mildly elated) episode.
For in-depth information, see WebMD's Bipolar Disorder (Manic Depression).
I second the "never diagnose yourself" statement.
I would also suggest changing how you think of yourself from "I am bipolar" to "I have bipolar (disorder)". Also, change "I am depressed" to "I have depression". And "I am an addict" to "I have an addiction".
It's more than just semantics. One defines and labels you as your illness, and the other recognizes you are a regular person with a treatable condition with which you are coping. One is encumbering, and the other is empowering.
Sometimes I have a hard time. I'm not sure if I'm depressed or not. But that atypical one, "Oversleeping, Fatigue, Extreme sensitivity to rejection, Moods that worsen or improve in direct response to events," does seem to describe me pretty well. It's certainly hard for me to motivate myself to get anything done. Even when "getting anything done" just means talking to friends. I get so lonely, because I have so few friends around here, but then I don't take advantage of the ones I do have. I don't call. I don't go on facebook and try to reconnect with those friends I do have. I isolate myself from people, and then wonder why I'm so isolated.
I stay home when I'd rather go out, because I don't know where I want to go, and I have no one to go there with. I'm 27 years old, and I feel like I'm not making the best use of y life.
It's hard for me. But I don't know if I'm actually sick, or just lazy and whiny, and need to get over myself.
I feel like everyone goes through hard times and can use a little help--even if some people have it worse than others. I don't want to overstate my struggles here, because they're nothing as hard as what some people go through. But I like the idea that this group is here to help anybody along, no matter which type of depression they have.