Major depressive disorder is the most common diagnosis that reflects the sadness and despair of someone experiencing depression. However, a clinician must evaluate symptoms carefully because several other diagnoses exist that might prove more appropriate. Depressed feelings may result because of medical conditions, substances such as drugs and other disorders such as dementia.
Basics
The diagnostic criteria for major depressive disorder include sad mood or loss of interest or pleasure in activities normally enjoyed. Secondary symptoms important for diagnosis include significant changes in appetite and weight, significant sleep changes, physical agitation or slowness, fatigue, feeling worthless, concentration problems and thoughts of death, according to the American Psychiatric Association's "Diagnostic and Statistical Manual." Major depressive disorder is diagnosed if an external situation or medical condition cannot account for the mood changes.
Dementia
Elderly people with dementia, such as Alzheimer's disease, go through disease stages in which depression represents a major symptom. This differential diagnosis can prove tricky as people with major depression sometimes report an inability to concentrate or remember certain things, similar to dementia. A thorough neurological exam and neuropsychological testing can help determine the most appropriate diagnosis.
Substances
The intake or cessation of certain substances can cause mood changes. An individual experiencing substance abuse and trying to quit may experience mood swings. Other medications or substances may themselves cause the onset of a depressive episode. A "substance-induced mood disorder" diagnosis occurs when there is a persistent mood disturbance judged to result from the direct physiological effect of a substance, such as a street drug, medication or toxin exposure, according to the American Psychiatric Association.
Medical Conditions
Sometimes medical conditions can lead to persistent depression, loss of interest or pleasure or irritability. In such cases, the most appropriate diagnosis may be "mood disorder due to a general medical condition," according to the American Psychiatric Association. This particular diagnosis can challenge the clinician to make because many different causative factors require consideration. Atypical features of depression may offer a clue for differential diagnosis, such as unusual age of onset.
Bereavement
The death of a loved one can cause significant depression and despair for an extended period. The symptoms may resemble those of major depressive disorder, such as sadness, insomnia, poor appetite and weight loss, but would be most accurately diagnosed as "bereavement." If the symptoms last longer than two months, then a clinician may diagnose major depressive disorder, according to the American Psychiatric Association.
Adjustment Disorder
People sometimes go through life stresses during which they temporarily feel down or depressed. Depressive symptoms that do not meet the full criteria for major depressive disorder and occur within three months of a clearly-identifiable life stressor receive a diagnosis of an "adjustment disorder with depressed mood," according to the American Psychiatric Association.
References
- "Diagnostic and Statistical Manual of Mental Disorders"; American Psychiatric Association; 2000.
- Behavenet: Clinical Capsule -- Major Depressive Episode
- Behavenet: Clinical Capsule -- Mood Disorder Due to a General Medical Condition
- Behavenet: Clinical Capsule -- Substance-Induced Mood Disorder
- Behavenet: Clinical Capsule -- Adjustment Disorder
