Depression can be very intense depending on the stage of depression you are going through. Depression can last for weeks at a time or it can linger for years. There are three forms that the doctor will try to distinguish between to see which one you should be diagnosed with. There is the short lasting form that is known as major depression and there is the longer lasting but less severe form that is known as Dysthynia. The third form of depression that your doctor can diagnose you with is known as an adjustment disorder with depressed mood. This particular form refers to a depressive reaction to a certain life event when the adjustment to the loss takes a longer amount of time to overcome and interferes with daily activities. Such an event would be a death or a divorce.
Bipolar Disorder- this disorder is also known as manic depressive illness which is another depressive condition that involves periods of major depression mixed with periods of mania. Mania is known as the term for abnormally high mood and extreme bursts of unusual activity or energy.
There are symptoms of depression that you should know about when someone you know is experiencing depression:
1) Conveying a depressed mood or sadness most of the time when you see them
2) Conveying that they have a lack of energy than they normally do
3) Conveying that they don’t enjoy certain things that they usually do
4) Conveying that they are no longer interested in hanging out with friends or family
5) Conveying that they are not able to concentrate on a particular event
6) Conveying that they have lost weight or have gained weight
7) Conveying that they are not getting the accurate amount of sleep.
8) Conveying that they are feeling guilty about something or they feel like they have no purpose in life.
9) Conveying that they are in pain or their body aches when really and truly there is nothing wrong.
10) Conveying that they are considering suicide

When someone you know has five or more of the symptoms that I have listed above for a period longer than two weeks, that person is more than likely depressed. The doctor will be able to let you know if that person is suffering from a major depression disorder.
Teens that are depressed are also known to show signs or symptoms of being depressed. You may notice that they have problems at school when they are normally angels at school. You may also notice that their grades have dropped when they normally make good grades in school. Some teens may also talk about dropping out of school or actually do drop out of school because they think that their condition will cause them to fail. For some teens who are depressed the thought of a failure at school will be more than they can bear. As a result they may turn to alcohol or drugs.
There are two types of depression, there is the depression that originates from a bad experience or event that has happened in your life and then there is the type that appears without cause which is the most common.