Psychiatry: basic sciences
Neuroimaging & investigations
This subject covers the tests psychiatrists use to look for physical causes of mental symptoms and to monitor treatment: blood tests, ECG, EEG, CT and MRI scans and specialised imaging. It is about knowing which test to order and what the result means.
Depth by stage, Pre-U → Consultant (details)
What is it?
There is still no blood test or scan that diagnoses depression or schizophrenia. Investigations in psychiatry are used to rule out other causes, such as thyroid disease, infection, brain tumours or drug effects, and to keep patients safe on medication.
Routine tests include full blood count, kidney, liver and thyroid function, glucose and lipids, and urine drug screens. Psychiatrists also order ECGs for heart rhythm, EEGs for suspected seizures or delirium, and CT or MRI scans when there are neurological signs, atypical features or late-onset illness.
Research imaging such as functional MRI and PET has taught a great deal about the brain in mental illness, but mostly is not used for individual diagnosis. Trainees learn both the practical uses and the research findings.
Why does a psychiatrist need it?
Missing a physical cause of mental symptoms can be dangerous, and many psychiatric drugs need monitoring (lithium levels, clozapine blood counts, metabolic checks). A psychiatrist must choose sensible, cost-effective investigations, interpret them, and explain results to patients without over-claiming what brain scans can show.
What level is expected at each stage?
Scale: 1. Aware → 2. Understands → 3. Applies → 4. Masters / Teaches. What the levels mean.
- Pre-UNot expected
- Pre-clinicalAwareAware of the basic principles of imaging and laboratory tests.
- ClinicalUnderstandsKnows which routine tests are ordered for common presentations and reads basic results.
- HousemanshipAppliesOrders and follows up routine blood tests, ECGs and imaging daily under supervision.
- Medical officerAppliesPlans the organic work-up for new psychiatric presentations and drug monitoring.
- Psych traineeAppliesSelects targeted investigations, interprets EEG/imaging reports and knows research imaging findings at exam level.
- Specialist / consultantMasters / TeachesSets investigation protocols, handles complex neuropsychiatric work-ups and teaches interpretation.
What are the key topics?
Laboratory tests
- Baseline screen for first presentations: FBC, renal, liver and thyroid function, glucose, calcium, B12/folate
- Infection screen where relevant (syphilis, HIV, others)
- Urine drug screening and its limits
- Therapeutic drug monitoring: lithium, valproate, clozapine levels
- Clozapine haematological monitoring
- Metabolic monitoring on antipsychotics (weight, glucose/HbA1c, lipids)
- Prolactin measurement
Cardiac and neurophysiological tests
- ECG and QTc interpretation before and during psychotropic treatment
- EEG in suspected epilepsy, delirium, encephalitis and before or after ECT where indicated
- Sleep studies (polysomnography) in selected cases
Structural imaging
- CT versus MRI: strengths and indications
- Indications for brain imaging in psychiatry: first-episode psychosis with atypical features, late-onset illness, neurological signs, cognitive decline
- Typical findings: atrophy patterns in dementias, white matter disease, tumours, hydrocephalus
- Incidental findings and how to handle them
Functional and research imaging
- Functional MRI and resting-state networks
- PET and SPECT, including amyloid and dopamine transporter imaging in dementia
- Magnetic resonance spectroscopy
- What imaging research has shown in schizophrenia, depression and OCD, and its clinical limits
How is it learned and assessed?
- Pathology and radiology teaching in medical school
- Daily ordering and review of tests as a house officer and medical officer
- Basic sciences in psychiatry training; examined in MMed Psychiatry Part I and MRCPsych Paper A
- Neuroradiology and neuropsychiatry case conferences during training
Typical textbooks and resources
- The Maudsley Prescribing Guidelines in Psychiatry — monitoring tables
- Lishman's Organic Psychiatry — investigations in neuropsychiatry
- Oxford Handbook of Psychiatry — practical investigation guidance
- MOH Malaysia Clinical Practice Guidelines (e.g. on schizophrenia, dementia)
Titles are widely used examples; editions change. Use university libraries or legitimate purchases.
Common questions
Can a brain scan diagnose depression or schizophrenia?
Not at present. Scans are mainly used to rule out other causes, such as a tumour or stroke. Research imaging shows group differences, but these are not reliable enough to diagnose an individual.
Why do patients on lithium need regular blood tests?
Lithium works within a narrow range: too little is ineffective and too much is toxic. It can also affect the kidneys and thyroid, so levels and organ function are checked regularly.