Major Depressive Disorder
The chief criterion for MDD is one or more major depressive episodes exclusive of manic, mixed, or hyponomic episodes, or episodes traceable to substance-induced mood disorders, and mood disorders due to general health considerations. Also, the depressive episodes in question must not be considered as leading to a diagnosis of MDD if they can be better explained by a diagnosis of schizoaffective disorder, or can be viewed as being superimposed on the conditions of schizophrenic disorder , schizeophreniform disorder, delusional disorder, or undifferentiated psychosis. DSM-IV-TR further notes that the depressive episodes to be considered by the diagnostician may be single or recurrent.
DSM-IV-TR gives standards for the evaluation of episodes suspected of being depressive in nature. A set of nine symptoms is given. Two of these are depressed mood and loss of interest/pleasure and the patient must have one of these two symptoms and at least enough of the remaining seven to make up a total of five. The remaining seven are: significant weight change, insomnia or hypersomnia nearly every day, psychomotor agitation or retardation nearly every day, fatigue nearly every day, excessive feelings of worthlessness or guilt nearly every day, diminished ability to think or concentrate nearly every day, recurrent thoughts of death or suicide.
Additionally, DSM-IV-TR mandates that a number of points be considered by the healthcare professional when he/she attempts a diagnosis on the basis of these symptoms. The most important of these is that the symptoms be severe enough to cause significant distress and/or problems in functioning in such areas as the patient’s social life and work life.
The Depression Center’s on-line pamphlet, “What is Depression?” lists the following as implicated in the etiology of MDD: genotype, stressful life situations (e.g. relationship problems, work problems), problems associated with neurotransmitters (e.g. serotonin), changes in certain structures within the brain, psychological/personality factors (e.g. low self esteem), and use of medications. There is a noticeable gender differential with respect to MDD with women being twice as likely to be diagnosed as suffering from MDD as men are.
An Author has made an extremely important point with respect to MDD and its relationship to lesser forms of depression. They have stated, “Normal and abnormal depression are on a continuum, one merging into the other. Although in most instances the extreme ends of the continuum are obvious, where normality ends and abnormality begins is often difficult to determine .” This makes reliability of diagnosis, even under the best of circumstances, difficult. Since, under the conditions that prevail in the modern American health system the person who makes the initial diagnosis of MDD (and often, in fact, subsequently treats it through prescribing an anti-depressant) is frequently a physician who is not trained in psychiatry or even someone who is not a physician at all, e.g. a nurse practitioner, the inherent difficulty of making an exact diagnosis is exacerbated. It is therefore the case that precise and reliable numbers associated with the disease are very difficult to obtain and numbers in which MDD can be broken out from numbers for depression generally suspect. There is a built-in indeterminacy with respect to figures reporting the incidence of MDD and lesser forms of depression and, because that is so, also with respect to assessments of the economic costs associated with the disease.