Organic Personality Syndrome

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Organic Personality Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Personality Syndrome, Organic

Disorder Subdivisions

  • None

General Discussion

Organic personality syndrome or organic mental syndrome is a mental disorder characterized by a short-term or long-term personality disturbance largely due to brain dysfunction. The ability to reason, remember, imagine, and learn may not be affected, but the individual's judgment may be so poor that continual supervision may be necessary. Left unattended, he or she may behave in ways that could cause difficult or dangerous problems.


In Organic Personality Syndrome, behavior changes and character traits are either exaggerated or at least different from usual. Symptoms usually show themselves in one of three basic patterns depending on the nature and location of the brain dysfunction.

The first and most common pattern is characterized by emotional instability, faulty social judgment, possible belligerence and/or an over-reactive temper. The person may engage in inappropriate social behavior without regard for the consequences (e.g. sexual indiscretions). The second pattern may include significant signs of apathy and indifference. The person has no concern for, or interest in, his or her immediate environment or former customary hobbies. Both of these patterns may be caused by damage to the frontal lobes of the brain (frontal lobe syndromes). The third pattern of behavior, seen in some disorders affecting the temporal lobe, is marked by a strong tendency to be humorless and overly redundant in both speech and writing, and, not infrequently, by overzealous religious devotion. Occasionally, the person may show extreme rage. One of the major changes in this behavior may be unreasonable suspiciousness or paranoid ideas. If the main symptom is outbursts of aggression or rage, the patient may be labeled as an "Explosive Type".


There are several possible causes for Organic Personality Syndrome. Frequently it is the consequence of structural brain damage from neoplasms (tumors), head trauma, or cerebrovascular disease involving the upper part of the brain and its blood vessels. Less commonly, it may be caused by endocrine disorders such as thyroid and adrenocortical (outer part of adrenal gland) disease, or by ingesting certain psychoactive substances (drugs that affect the mind or behavior). The syndrome may be of short duration if caused by medications, drug abuse, or certain types of tumors that are surgically removed. It may be of long duration if it is secondary to structural brain damage.

Affected Populations

Organic Personality Syndrome is a prevalent disorder that affects males and females of all ages in equal numbers. It is often a symptom of an underlying disease or condition.

Standard Therapies

Treatment of Organic Personality Syndrome depends upon the cause. If it is due to medication or drug abuse, once the cause is identified, corrective action can be taken and the person's behavior usually returns to normal. If it is due to a brain tumor (neoplasm), much depends on the tumor type, the patient's age, tumor location, and success of therapy. Surgery may be effective, and in some cases patients recover with little or no permanent change in their intellectual abilities and quality of life. If the Organic Personality Syndrome is due to another underlying neurological disorder, appropriate treatment for that disorder may be helpful.

Investigational Therapies

Some research has been done on the effectiveness of certain antidepressant drugs. In the cases tested, patients had Organic Personality Syndrome with no other underlying neurological diseases, combined with depression. Many patients improved on antidepressant drugs and remission occurred in some patients.

Information on current clinical trials is posted on the Internet at All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010


For information about clinical trials sponsored by private sources, contact:



Comprehensive Textbook of Psychiatry. 5th ed.: Harold I Kaplan & Benjamin J. Sadock eds.; Williams & Wilkins, 1989. Pp. 599-641.


Psychiatric Disorders in Children and Adolescents After Severe Traumatic Brain Injury: A Controlled Study. J. E. Max, et al. J Am Acad Child Adolesc Psychiatry (March 1998, 37 (8)). Pp. 832-40.

Treatment of Organic Personality Syndrome with Low-Dose Trazodone. C. A. Tejera, et al., J Clin Psychiatry (August 1995, 56 (8)). Pp. 374-75.

Neuropsychological and Neuropsychiatric Findings in Right Hemisphere Damaged Patients. N. Motomura, et al., Japan J Psychiatry Neurol (December 1988, 42 (4)). Pp. 747-52.

Cognitive Outcome and Quality of Life One Year After Subarachnoid Haemorrhage, P. McKenna, et al., Neurosurgery (March 1989, issue 24 (3)). Pp. 361-367.

National Survey of Patterns of Care for Brain-Tumor Patients, M.S. Mahaley, Jr, et al., J Neurosurg (December 1989, issue 71 (6)). Pp. 826-836.



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NIH/National Institute of Mental Health

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For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see