The psychiatrist tries with all available methods to create as accurate a picture as possible of the patient who comes to his office. The psychiatric examination begins with a thorough medical history - both from the patient himself and from his immediate environment. He deepens the information obtained from the history by performing additional examinations - imaging, laboratory tests, psychological tests and others. Laboratory tests are an extremely valuable diagnostic tool and allow us to step more confidently into the 'maze of psychiatric diagnoses'.
Table of contents:
- Laboratory in psychiatry?
- Exclusion of somatic illness
- Laboratory tests in psychoactive substance users
- Monitoring the effects of prescribed treatment
- Summary
Laboratory in psychiatry?
Psychiatrists diagnosing their patients have more and more so-called objective diagnostic tools at their disposal to exclude or confirm a possible diagnosis. This is because it is often the case that different psychiatric disease entities have a similar clinical picture and that the history taken from the patient and his or her family alone is insufficient to make an accurate diagnosis. And a correct diagnosis is the opportunity to prescribe the most effective treatment and start the healing process, rather than navigating through a maze of diagnostic puzzles or an even wider range of treatment regimens. Therefore, the practising psychiatrist has at his disposal and should make use of additional tools, such as laboratory tests, imaging tests or various psychological tests - all of which have specific scales, boundaries of normality and their interpretation does not depend on the skills of a particular doctor. We say that they are "objective". Laboratory tests are used for several purposes in psychiatry.
Exclusion of somatic disease
According to modern diagnostic criteria , the diagnosis of a specific psychiatric disorder requires the exclusion of the presence of a somatic disease. Many of these diseases have psychiatric disorders in their clinical picture: depressive, manic, anxious, delusional, delirious, delirious, which are very likely to disappear when we start treating the underlying disease correctly. Somatic illnesses are also diagnosed on the basis of the patient's medical history, physical examination and precisely the additional tests, including laboratory tests. With the help of tests such as blood count, biochemical tests of serum or plasma, serological tests and cerebrospinal fluid tests, we can quickly rule out or suspect that the patient's mental disorder has an organic basis.
For example, neurological diseases very often present with quantitative and qualitative disorders of consciousness, dementia, personality and mood disorders. In such cases, an assessment of the cerebrospinal fluid is extremely useful to exclude, among other things, meningitis, encephalitis, demyelinating diseases (e.g. Alzheimer's disease), systemic lupus, etc. Of course, laboratory tests must always be preceded by a thorough medical history and physical examination of the patient!
Endocrine diseases (associated with endocrine abnormalities) very often have various types of psychiatric disorders in their clinical picture. Hyper- and hypothyroidism of the thyroid, adrenal and pituitary glands is detected by performing specific determinations of the concentration of individual hormones over the course of a day (so-called diurnal profile). The exclusion of endocrine disorders is extremely important in making a strictly psychiatric diagnosis, because, for example, effective treatment of depression (which is a common symptom of overproduction of glucocorticosteroids, i.e. substances produced by the adrenal glands) is very difficult if permanent endocrine disorders are at the root of it.
Laboratory tests in users of psychoactive substances
When a patient presents who is aggressive, agitated, with whom verbal-logical contact is impaired, he should practically immediately have a panel of toxicological tests performed, which can provide the physician with valuable clues. The management will be different in a person who is in a state of mania but in the course of bipolar affective disorder, and quite different in a person who is under the influence of psychostimulants. The symptoms in both such patients may be virtually the same, hence the important role of laboratory tests to rule out intoxication. It is worse if we do not have the appropriate laboratory tests and do not know what substance the patient is under the influence of, and this is often the case with new psychoactive substances, or so-called 'legal highs'. But this is a topic for a separate article...
Support from a psychiatrist, photo: pantherstock
Monitoring the effects of the prescribed treatment
The drug treatment that a patient takes has positive effects, but also, unfortunately, possible side effects. Some of the pairs: drug side effects are very well understood, studied and predictable. E.g. antidepressants and neuroleptics are largely metabolised by liver enzymes, so appropriate laboratory tests should answer the question of how efficient the liver is in a given patient before implementing such treatment. Metabolised drug products are in turn excreted by the kidneys, so their condition also needs to be taken into account in the proposed treatment (e.g. the drug dose may need to be reduced).
Treatment with the very potent neuroleptic, clozapine, on the other hand, requires frequent monitoring of blood morphological parameters, as the most serious side effect of this drug is agranulocytosis, i.e. a very low level of one of the leukocyte subtypes, which renders the patient's immune system completely inefficient, resulting in frequent and severe infections.
Lithium salts, or mood-stabilising drugs, need to be at a constant level in the blood serum. We say that they have a 'narrow therapeutic index', meaning that fluctuations in the blood concentration of this drug are very bad for the success of treatment and for the patient's other organs. Therefore, before starting lithium therapy, it is advisable to perform tests: blood count, total urine, determination of creatinine and urea levels, assessment of thyroid function, ECG and pregnancy tests.
Before a patient is treated with electroconvulsive therapy (which may be the only effective treatment for drug-resistant depression), cardiorespiratory and gastrointestinal function should be examined. An ECG, blood count, electrolyte levels (especially sodium, potassium, calcium and magnesium) and blood glucose levels are essential.
Summary
It is worth emphasising once again that additional investigations (especially imaging and laboratory tests) have a key role in the diagnostic process of mental illness. Subsequent scientific studies look for cause-and-effect relationships between various types of lesions in the central nervous system or an increase/decrease of a particular compound in the blood and the occurrence of mental illness. Laboratory tests make it possible, at the very beginning of the diagnostic process, to exclude many somatic diseases (e.g. thyroid disorders, adrenal disorders), organic disorders of the central nervous system or conditions resulting from psychoactive substance intoxication. These are important diagnostic tools, achievements of modern medicine, and it is worth and necessary to use them.
