There are several forms of depression that are generally not understood or treated.
Dysthymia: A person with dysthymia will be in a bad mood for more days than not for at least a few years.
Bad moods can include feelings of hopelessness, impaired cognitive function (eg, difficulty concentrating, making decisions), loss of appetite or overeating, low energy or fatigue, low self-esteem, and trouble sleeping. (more or less sleep).
However, these all kinds of depression can be overcome by taking certain measures. You can also visit http://edupression.com to know more about how to prevent depression.
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Cyclothymia: Like bipolar disorder, cyclothymia is a chronic mood disorder characterized by many periods of depression and hypomanic symptoms.
Cyclothymia differs from bipolar in that symptoms are usually tested for at least years without delay.
Major Depression: An extreme form of dysthymia, major depression can be debilitating if not treated properly.
Major depression is usually characterized by the same symptoms as dysthymia with increased intensity and loss of motivation, loss of enjoyment, feelings of worthlessness and guilt, recurrent thoughts of death or suicide.
Contributing Factors: While there is no clear cause of depression, there are many factors that contribute to the severity, duration, and frequency of depressive symptoms.
Contributing factors can also play a large role in the overall treatment design. A common factor that contributes to signs of depression is loss.
Whether losing a loved one, job, beloved pet, moving to a new house, marriage, divorce; any major change/loss/transition can cause signs of depression or worsen existing signs or disorders.