Signs of Clinical Depression
The National Institute of Mental Health states that the two most common forms of clinical depression are major depression and dysthymia, although other disorders, such as bipolar disorder and seasonal affective disorder also have depressive episodes. Certain symptoms are shared by the different forms and types of clinical depression. Clinical depression manifests in physical, behavioral and emotional symptoms. Among the most common physical signs of clinical depression are fatigue and feeling frequently tired or as though no matter how much you sleep, you still don't feel rested, changes in appetite and normal sleep patterns and unexplainable aches and pains, such as frequent headaches or stomachaches. Additionally, these symptoms often do not respond to conventional treatments; taking an aspirin for your headache may not help. Behavioral symptoms of clinical depression include any change in your usual activities and responsibilities. You may experience a loss of interest in social activities, have decreased interest in sex or activities you once found pleasurable and fun, and you might find it difficult to concentrate or focus on the most seemingly basic tasks. Emotional signs of clinical depression are probably the most easily recognizable for many people. You might find yourself crying more frequently for no explainable reason, feel hopeless, sad or dejected, have a lowered level of self-esteem or feel irritable or nervous. Your use of alcohol and other mood-altering substances may increase, in an attempt to self-medicate and numb your feelings. In severe cases, some people may experience thoughts of death or attempt to commit suicide.
Major Depressive Disorder
Major depressive disorder is a debilitating condition that is characterized by the presence of at least one major depressive episode, as stated in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. A major depressive episode consists of five or more of the following symptoms for a two week (or longer) time period. The criteria include feeling significantly depressed most of the time, decreased interest and pleasure in regular, once-enjoyable activities, noticeable changes in weight, sleep difficulties almost every night, chronic fatigue, problems concentrating and making decisions almost every day, feelings of restlessness or agitation as observable by others and/or sucidal ideation or frequent thoughts of death. These symptoms must be severe enough to cause a significant impairment in your day-to-day functioning and are not attributable to other conditions, such as substance abuse or bereavement.
There are two types of major depressive disorder – single and recurrent. In a single episode of major depression, you experience one major depressive epsiode. In recurrent depression, you have had at least two major depressive episodes.
Dysthymia, also known as dysthymic disorder, is a less severe form of clinical depression. Although dysthymia is less severe, it is a long-term disorder, lasting two years or longer. While your symptoms may not be as debilitating as those of major depression, they can still cause a significant impairment in your well-being and your ability to function. You may also experience several major depressive episodes over the course of your life.
National Institute of Mental Health: Depression https://www.nimh.nih.gov/health/publications/depression/complete-index.shtml
American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, DSM-IV-TR. 1994