Types of Depression and Associated Symptoms
Although depression is a clearly defined disorder with mental and physical symptoms, unlike other disorders, doctors cannot diagnose it using a blood panel or other form of lab test. Instead, they use carefully developed clinical guidelines as defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM).
Depression is distinguished into various forms. The most common are major depressive disorder and dysthymic disorder.
Major Depressive Disorder (Major Depression)
Major depressive disorder can be very disabling, preventing the patient from functioning normally. A combination of symptoms sabotages the patient’s ability to sleep, study, work, eat, and enjoy formerly pleasurable activities. Some people may experience only a single episode, while others experience recurrent episodes.
Dysthymic Disorder (Dysthymia)
Dysthymia, also known as chronic mild depression, lasts longer than two years. Symptoms are not disabling or as severe as those of major depression, however the patient finds it difficult to function normally and does not feel well. A person with dysthymia may also experience periods of major depression.
Psychotic depression is a severe depressive illness that includes hallucinations, delusions, or withdrawal from reality.
Postpartum Depression (Postnatal Depression)
Postpartum depression, also known as postnatal depression (PND), affects 10% to 15% of all women after giving birth. This is not to be confused with the “baby blues,” which a mother may feel briefly after giving birth. The development of a major depressive episode within a few weeks of giving birth likely indicates PND. Sadly, many of these women go undiagnosed and suffer for long periods without treatment and support.
Seasonal Affective Disorder (SAD)
The incidence of SAD increases along with the distance from the equator. A person who develops a depressive illness during the winter months with symptoms that go away during spring or summer may have SAD. Accumulating evidence points to vitamin D deficiency as a contributing factor in SAD and in other forms of depression.6
Bipolar Disorder (Manic-Depressive Illness)
A patient with bipolar disorder experiences (oftentimes extreme) highs (mania) and lows (depression) in mood. The frequency at which an individual reverts from mania to depression, and vice-versa, determines where they lie on the bipolar spectrum—a diagnostic tool used to measure the severity of bipolar disorder.