Feeling sad is not anything unusual. There are various things that can make one sad but that is just a passing phase and some other stimulants remove this sad feeling. But when this stays on and interferes in the daily life of the person then it is a matter of concern. It means depression has set in and the person is not at the best of mental health. It not only affects the person but also those around him or her. So it needs medical attention though many people tend to avoid it completely. These days research into the psychological health of people has resulted in development of many medicines, psychotherapy and other different methods for treatment of depression.

But are all the depressions same? No, they are not and a look into the various types of depression will throw more light on to the matter. The commonest of all the depressions are the major depressive disorder and the dysthymic depressive disorder.

Major depression or major depressive disorder is that type of disorder when it interferes with the daily life and routine of the person. It can prevent a person from eating, sleeping and acting normally and such depression may occur once or recur several times during a lifetime. The dysthymic depression is one that continues for quite a long time extending over a year or two. This can get combined with major depression once or twice. But in the normal condition it is less severe than the major one as it interferes less with daily routine. But the person gets a general feeling of sadness during this whole period.

The new mothers can get postpartum depression in about a month after delivery and this is noticed in not more than 10 to 15 percent women.  Sometimes people get depressed with the absence or lessening of sunlight. This condition is known as Seasonal Affective Disorder (SAD) and has the tendency of lifting as spring and summer progress. The treatment of SAD involves light therapy though it needs to be supplemented with medications.

Severe form of depression results in the psychotic disorder where the depression goes to such an extent that the person loses contact with reality and often hallucinates and experiences delusions. Another disorder that is loosely associated with depression is bipolar disorder where the person goes from an absolute high to deep depression in a cycle.