Notes: Diagnostic tests in psychiatry

History collection and mental examination are the major diagnostic measures which are commonly used in psychiatry. For the differentiation of any organic pathology and to identify the co morbidities various other diagnostic measures are used.
  Purposes

• To screen for any potential diseases
• To rule out any organic pathology
• To have a baseline data of investigations

Blood examination

1. Routine blood examination- Routine blood investigations on complete blood count is done. Patients who get Tb.Clozapine, an atypical antipsychotic should be monitored for WBC count as one if its side effects are Agranulocytosis.
2. Thyroid function tests- It includes T4 & TSH in particular. It is done to assess the correlation between hypothyroidism and depression.
3. Kidney function tests- Renal function tests are often done among patients who take Lithium as poor renal clearance can result in lithium toxicity. Creatinine clearance is also used to calculate the lithium dosage.
4. Neurotransmitter level monitoring- As the most of the psychiatric conditions has an underlying neurochemical changes levels of neurotransmitters like epinephrine, serotonin and dopamine level are done rarely.
5. Lithium level- Blood lithium level monitoring is done to know the effectiveness of treatment and to avoid lithium toxicity. It is usually checked twice in a week while stabilizing the patients mood and after that once in a month. The blood is usually withdrawn after 8-12hours after last dose.
6. Alcohol level- Alcohol level in blood is usually monitored before starting with disulfiram therapy and also for legal indications. Amount of alcohol in blood greater than 100mg/dl is considered as legal intoxication.

EEG- It is one of the commonly used diagnostic test in Psychiatry to assess the electrical activity of brain. This helps in identification of seizure causes and any brain lesions. A standard non invasive EEG takes about 1 hour. The patient will be positioned on a padded bed or table, or in a comfortable chair. To measure the electrical activity in various parts of the brain, a nurse or EEG technician will attach 16 to 20 electrodes to the scalp. The brain generates electrical impulses that these electrodes will pick up. To improve the conduction of these impulses to the electrodes, a gel will be applied to them. A temporary glue will be used to attach them to the skin. No pain will be involved with this procedure.
  Nurses responsibility

• If the patient routinely takes seizure medication to prevent seizures, antidepressants, or stimulants, he or she may be asked to stop taking these medications 1 to 2 days before the test.
• The patient may be told not to consume caffeine before the test.
• The patient should avoid using hair styling products (hairspray or gel) on the day of the exam.
• It is prudent to have someone take the patient to the EEG location, especially if he or she has been asked to stop taking seizure medications.
• If the patient is having a sleep EEG, he or she may be asked to stay awake the night before the exam

CT and MRI
 Computerized tomography (CT) and magnetic resonance imaging (MRI) are the most common head scanning techniques used in emergency medicine. CT is quicker and cheaper, has less movement artifact, and is excellent at delineating acute hemorrhage, calcification, and bony anatomy. Unfortunately, CT exposes patients to radiation and poorly visualizes white matter or posterior fossa pathology. MRI is outstanding for well-defined tissue contrast in multiplanar views and excellent for identifying demyelination or metastatic processes, but may be contraindicated for patients with implanted metallic objects such as pacemakers, certain vascular clips or stents, and certain orthopedic devices. Some patients cannot tolerate the narrow space surrounding them during an MRI. Psychological tests

1. Intelligence tests

The intelligence quotient (IQ) is the ratio of MA to CA (chronological age), multiplied by 100 to eliminate the decimal point. Mental age is obtained by intelligence tests

1. Wechsler Adult Intelligence Scale (WAIS)

The Wechsler Adult Intelligence Scale (WAIS) is the best standardized and most widely used intelligence test in clinical practice today. It was constructed by David Wechsler at New York University Medical Center and Bellevue Psychiatric Hospital.

1. Binet Kamath Intelligence test
2. Personality tests

• Questionnaires:
• MMPI (Minnesota Multiphasic Personality Inventory)
• 16-Personality Factor test
• EPI (Eysenck personality inventory)
• Projective Tests:
• Rorschach ink blot test: Consists of a set of 10 ink blots. These cards are presented to the patient at a time and he is asked to give his interpretation of the inkblot. Five of them are black and white and five are multi colored. Each card is presented in a sequential order, one at a time.
• TAT (Thematic Appreciation Test): It has a series of 30 pictures. The patient is asked to create a story of what he perceives in the picture. Each card is presented one at a time. Based on each card the individual is asked to make a story on

    What is going on in the picture?     What has led to this scene?     What would happen in such a situation?

• Draw a person test
• Draw a family test
• Sentence completion test (SCT): A large number of 75-100 incomplete sentences are given to the patient and he or she asked to complete them. The test helps in identifying the patients fears, goals, or concerns etc
• Word association- The examiner will utter a series of words, one at a time. After each word the individual should reply quickly the first word which comes to his mind. There are no right or wrong responses. The content of response, reaction time and association behavioural expressions are interpreted by analysis.

  Nurses role

• The psychiatric nurse should have knowledge about psychological tests. This will enable her to clarify the doubts of the patients and relatives regarding psychological tests they have to undergo
• The nurse should reassure the patient about the safety of the tests and confidentiality of the observations of the psychologist
• The nurse observes the patients behavior and the changes, which occur once therapy is commenced
• Nurse observes, informs, and records these changes in the patients chart
• The nurse can also interpret the findings of the various tests and then plan nursing care accordingly