This paper examines neurocognitive disorders (NCDs) as classified in the DSM-IV-TR and DSM-5, tracing the evolution of terminology and diagnostic criteria across both editions. It reviews the essential psychopathology of delirium, dementia, and amnestic disorders, including their causes, symptoms, and management. The paper then compares DSM-IV-TR and DSM-5, highlighting key changes such as the replacement of "cognitive" and "organic" with "neurocognitive," the introduction of major and mild NCD categories, and the expanded etiological subtypes. A fictional case study of an 85-year-old woman diagnosed with progressive dementia and possible Alzheimer's disease illustrates how these diagnostic frameworks apply in clinical practice.
The first of five clusters of mental disorders covers neurocognitive disorders — that is, dementia, delirium, amnestic and other cognitive disorders in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and organic, including symptomatic mental disorders in the tenth revision of the International Classification of Diseases (ICD) (Sachdev et al., 2009). The term neurocognitive has replaced cognitive and organic, respectively, in these two documents. The disorders in this cluster distinguish themselves by possessing demonstrable neural substrate abnormalities, cognitive symptoms, and deficits. The causes of these disorders vary, but they share common neurobiological characteristics that set them apart from any of the other disorder clusters (Sachdev et al., 2009).
Delirium is a cognitive disorder characterized mainly by a decreased awareness of one's environment, often described as a clouding of consciousness (Maxmen & Ward, 1995). Its signs occur without warning over the course of many hours to days, and fluctuate erratically, especially at night and in the dark. Other signs and symptoms include agitation and fright, illusions, hallucinations, incoherent speech, a disturbed sleep-wake cycle, and disorientation to time and place. Behavioral changes can be sudden and unexplained, and accidents often occur in delirious patients. The cause may be medical, surgical, chemical, neurological, or related to sensory isolation — often in an intensive or cardiac care unit. It can be mistaken for normal personality traits, dementia, strokes, or schizophrenia. Management consists of all measures to keep the patient alive, prevent brain damage, and prevent self-harm. Review of family history, referral to a physician, careful nursing care, constant observation, and physical control are also often called for (Maxmen & Ward, 1995).
Dementia involves a loss of intellectual abilities, particularly memory, judgment, abstract thinking, and language, accompanied by personality changes and impaired impulse control (Maxmen & Ward, 1995). The condition may develop gradually or suddenly, as after a fall or head injury. Deterioration of functions may go unnoticed for months or years, or may be mistakenly attributed to normal aging. Its subtypes include Alzheimer's disease (the most common form), vascular dementia, dementia associated with medical conditions, and substance-induced dementia. Secondary dementias may be treatable. Dementia is life-shortening and renders patients susceptible to medical illness and delirium. Its incidence rises with age, most commonly between ages 70 and 80. Biological causes differ according to subtype, while psychological causes depend on one's personality and circumstances. During diagnosis, dementia may be mistaken for delirium, pseudodementia, or depression. Management or treatment may take the form of biomedical interventions, such as calming medications, or psychosocial interventions, including appropriate patient care and family counseling (Maxmen & Ward, 1995).
Amnestic disorders involve loss of memory, often due to a specific occurrence such as a strike to the hippocampus or exposure to toxins like alcohol (Maxmen & Ward, 1995). Memory of remote events may deteriorate while other mental functions remain intact. These disorders are managed by eliminating alcohol use and exposure to toxins, improving nutrition, and controlling hypertension (Maxmen & Ward, 1995).
In the DSM-IV-TR, organic mental disorders were grouped into three categories: (1) delirium, dementia, and amnestic and other cognitive disorders; (2) mental disorders due to a general medical condition; and (3) substance-related disorders (American Psychological Association, 2000).
Delirium is described as a disturbance of consciousness with changed cognition that develops over a short period (American Psychological Association, 2000). It can be caused by a medical condition, a substance, multiple causes, or some unknown or indeterminate factor. Other features include a disturbed sleep-wake cycle, disturbed psychomotor behavior, emotional disturbances especially at night or when stimulated, and nonspecific abnormalities such as tremor or changes in reflex and muscle tone. Cultural and educational backgrounds are important considerations when evaluating cases. Children, older adults, and men are especially susceptible. Delirium is most prevalent among those aged 55 or older in the general population; approximately 10–15% among hospitalized older persons upon admission; 60% among nursing home residents aged 75 and older; 30–40% of hospitalized AIDS patients; and up to 80% among those with terminal illnesses. It is most commonly misdiagnosed as dementia due to overlapping memory loss. It must also be distinguished from brief psychotic disorders, mood disorders with psychosis, acute stress disorder, and dissociative symptoms (American Psychological Association, 2000).
Dementia, as defined in the DSM-IV-TR, is a condition of multiple cognitive deficits resulting from the direct effects of a general medical condition, a substance, or multiple causes (American Psychological Association, 2000). Dementia disorders share a common symptom profile but differ in their causes. Recognized causes include Alzheimer's disease, vascular disease, HIV disease, head trauma, Parkinson's disease, Huntington's disease, Pick's disease, Creutzfeldt-Jakob disease, other general medical conditions, substances, and multiple causes. Memory impairment is its most essential feature, often accompanied by aphasia, apraxia, agnosia, or disturbed executive functioning. Dementia usually develops late in life, especially beyond age 85, and is progressive and irreversible. It can be misdiagnosed as delirium, amnestic disorder, another type of dementia, mental retardation, manic-depressive disorder, malingering, factitious disorder, or the normal deterioration of cognitive abilities due to aging (American Psychological Association, 2000).
Amnestic disorders, according to the DSM-IV-TR, are disturbances in memory functioning due to the effects of a medical condition or a substance (American Psychological Association, 2000). They share the common symptom of memory impairment but differ in their causes, which include a general medical condition, a substance, and unspecified factors. They are accompanied by confusion, disorientation, some attention problems, denial of the condition, lack of initiative, and changed personality functioning. Traumatic brain injury, stroke, cerebrovascular injury, exposure to neurotoxic substances, prolonged substance abuse, or sustained nutritional deficiency may lead to these disorders. They may be mistaken for dissociative amnesia, dissociative disorders, or memory disturbances caused by intoxication or withdrawal from abused drugs. They should also be differentiated from malingering and factitious disorder (American Psychological Association, 2000).
"DSM-5 NCD categories, subtypes, and domains"
"Key differences and Task Force guiding principles"
"85-year-old diagnosed with dementia and Alzheimer's"
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