10 Laboratory Tests Used In Diagnosis of Mental Diseases

10 Laboratory Tests Used In Diagnosis of Mental Diseases !

Of late, for the perfect diagnosis of mental diseases and various psychologi­cal dysfunctions and syndromes, it has become essential to make various laboratory tests. Thus, today laboratory tests are playing quite prominent role in psychiatry than ever before.


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More specifically, laboratory tests help in the screening for physical as well as mental illness, for improving diagnostic reliability, for monitoring treatment and above all for continuing research in psychiatric illness. However psychiatric diagnosis should not be made based alone one the laboratory tests. Laboratory tests should be supplemented with clinical diagnosis.

Before starting psychiatric treatment on any patient a medical history and routine medical laboratory tests like blood pressure, blood sugar, thyroid test, E.E.G., E.C.G., urine tests are essential. They are discussed below briefly as suggested by Kaplan and Sadok.

1. Neuro Endocrine Tests:

These tests are required to find out if there is hypothyroidism which can produce symptoms of depression. Findings of some studies indicate that about 10 per cent of the patients complaining depression and related fatigue a hypothyroid disease. Lithium can also cause hypothyroidism. Mental retardation is caused by neonatal hypothyroidism and the disease can be prevented if diagnosis is made at birth.

2. Thyrotropin:

Releasing Hormone Stimulation Test (T.R.H.). The T.R.H. stimulation which applied on Patients having marginally abnormal thyroid secretion cause of clinical depression. This test is also used in with possible lithium induced hypo-thyroidism.

3. Dexamethasone Supression Test (D.S.T.):

This test is used to confirm a diagnostic impression of major depression with Melancholia (D.S.M III classification) or endogenous depression. The D. S.T. can be used to follow the response of a depressed person to treatment. Some evidences are there which suggest that a positive D.S.T. will have a good response to somatic treatment such as electro convulsive therapy (ECT) or cyclic antidepressant therapy.

4. Catecholamines:

Patients suffering from carcionoid tumors, who eat foods high in serotonin who at times take phenothiazine medication, the serotonin metabo­lite 5-hydroxyindoleacetic acid is found in excess in their urine. High levels of urinary norepinephrine and epinephrine have been found in some patients with post-traumatic stress disorder.

It is observed that the norepinephrine metabolic 3-methoxy-4 hydroxyphenylglycol (MHPG) levels is decreased in patients with severe depressive disorders, particularly in those patients who attempt suicide. The amount of 5-HAA in cerebrospinal fluid in low is persons who are suffering from suicidal depression and who indicate anti-social aggressive or/and impulsive personality traits.

5. Test for Plasma Levels of Psychotrophic Drugs:

Patients taking psychotrophic medicine should have regular measure­ments of their plasma levels of the prescribed drug. Particularly for drugs like lithium this test is essential.

6. Cyclic Anti-Depressants:

Before starting cyclic anti-depressants on patients it is necessary to take E. C.G. test to acertain about conduction delays which may lead to heart block at therapeutic levels. In fact, some experts believe that all patients on prolonged cyclic anti-depressant therapy should undergo an E.C.G. (Electro Cardiograph) test once in a year.

7. Base Line Thyroid Function Test:

Patients on lithium should have base line thyroid function tests, renal function tests and base line E.C.G. Patients on lithium should be regularly monitored as there is a narrow therapeutic range beyond which card problems and C.N.S. effects can occur.

8. Polysomnography:

It consists of a number of tests such as E.E.G., E.C.G. and E.M.R (Electromyogram). These tests are conducted in a number of psychology. Disorders like insomnia, nocturnal myoclonus, sleep apnea, enureses, sonambulism, seizure disorders, impotence, vascular headaches, gastro esophogeal reflux and depression.

9. Electro Encephalography:

The E.E.G. is used in the assessment of organic mental disorders and in diagnosis of specific seizures disorders, space occupying lesions and injuries, vasculars, lesions, encephalopathies etc. This test is a must for epileptic patients.

10. Evoked Potentials:

Evoked potential means the evoked response of brain electrical activity to repetitive sensory stimuli. These responses can be segregated from the spontaneous E.E.G. activity by computer averaging techniques called Brain Electrical Activity Mapping (B.E.A.M.) which produces a topographic colour map of brain activity.

Different latencies and wave patterns help to locate lesions starting from the end organ through the N. system to the cerebral cortex. More often than not defects in these pathways are not otherwise evident. Some studies show that in schizophrenic patients there is increased asymmetric beta wave activity in certain regions and increased delta wave activity is present and is most visible in the frontal lobes.

Besides the above laboratory tests required for psychiatric diagnosis treatment and monitoring other latest tests like Radio isotope brain Scanning, Radio isotope cisternography. Nuclear Magnetic Resonance Imaging (NMR or MRI) Positron Emission Tomography (C.T.), Regional cerebral blood flow technique etc. are used to diagnose various psychotic and psychoneurotic diseases caused by brain disorders.

Submitted by : Dr. Jason, Category : Mental Disorders, Tag : Mental Disorders