Facts on Mental Health

Organic Mental Disorders Include :

  1) Delirium
  2) Dementia
  3) Organic Amnestic Syndrome

Delirium

Delirium is the commonest organic disorder seen in clinical practice. 5-15% of all patients in medical and surgical inpatient units are estimated to develop delirium. Delirium is characterised by following features :

1) Clouding of consciousness (characterised by decreased awareness of surroundings and decreased ability to respond to environmental stimuli)

2) Disorientation associated with a decreased attention span and distractibility

3) Disturbance in perception mainly visual like illusions, misinterpretations and hallucinations

Important causes of Delirium include the following :

1) Metabolic causes

2) Endocrine causes

3) Drugs (both ingestion and withdrawl can cause delirium)

4) Nutritional deficiencies

5) Systemic infections

6) Intracranial causes

Dementia

Dementia is a chronic organic mental disorder characterised by the following features :

1) Impairment of intellectual functions

2) Impairment of memory (predominantly recent memory)

3) Deterioration of personality with lack of personal care

Impairment of all functions occur globally, causing interference with day to day activities and interpersonal relationships. There is impairment of judgement and impulse control and impairment of abstract thinking. There is no impairment of consciousness. The course of dementia can be progressive, stationary or reversible.

Organic Amnestic Syndrome

Organic Amnestic Syndrome is characterised by the following clinical features:

1) Impairment of memory due to an underlying organic cause

2) No disturbance of consciousness and attention (unlike Delirium)

3) No disturbance of global intellectual functions, abstract thinking or personality (unlike Delirium)

The impairment of memory is characterised by a severe impairment of recent memory or short-term memory (inability to learn new material). This is associated with impaired remote memory or long-term memory (inability to recall previously learnt material). There is no impairment of immediate memory (i.e. immediate retention and recall).

As recent memory is more sverely disturbed, very remote events are better remembered, especially in the intial stages. Recent memory impairment also leads to disorientation in time and place. To fill in the memory gaps, patient uses imaginary events in the early phase of illness.

Amnestic syndrome should be differentiated from delirium and dementia. This can be accomplished on the basis of pattern of memory loss.