The separation of psychiatry and neurology has arguments that support the split or the reverse.


Neurologists focus objectively on organic nervous system pathology whereas psychiatrists lay claim to illnesses of the mind.


Functional imaging and genomics latterly to confirmed that our mental life has its roots in the anatomy, physiology, neurochemistry and immunology of our brain.

A brief useful discussion can be found in the Wikipedia article on neuropsychiatry.  The author describes the inside the skin perspective of neurology whereas psychiatry looks at the outside the skin causation including personal, interpersonal and cultural factors.


It was Professor David Marsden in the 1970s who discussed movement disorders in terms of “lumping” or “splitting” and it would seem that a similar discussion can take place here, with regard to either a dichotomy or neurology in psychiatry being “at two ends of a causal continuum”.


It is argued that no psychiatric disorder has been completely mapped.  This reflects that the neural correlates of psychiatric disorders  within its infancy, rather than suggesting that such links will not be found.


The separation of neurology from psychiatry is best described by the focus of the neurologist on the organic structural history focusing on where in the nervous system the problem is taking place, physical examination with objectivity, followed by an organic investigation leading to disease or symptom orientated management.


The psychiatrist focuses on the rich description of mental phenomena, well developed interviewing skills, understanding multiple causation, appreciation of individual differences, interpersonal context and then using psychological and behavioural therapies though also pharmacotherapy.

The problem with the separation of neurology from psychiatry, is that there are now more than 11,900 psychiatrists registered with the GMC and approximately 500 neurologists in active clinical practice.


It is my hypothesis that psychiatrists find themselves much more vulnerable in the setting of not having on tap neurology then the other way around.




For the purposes of this discussion, diseases of the spinal cord, peripheral nervous system and muscle will form a future consideration.  Any disorder however that leads to acute pain will link with anxiety, whereas chronic pain whatever the cause, more commonly generates depression.  Sleep disturbance will impact on both.  American neuropsychologists, such as Dr Michael McCrae have emphasised how pain and any injury will impact on the psychological and emotional state, as well as leading to cognitive impairment including deficiencies in memory, attention and concentration. 

It is my opinion that anyone involved for instance in medico-legal practice, concerning head and brain injury must read Mr McCrae’s book on Mild Traumatic Brain Injury and the Post Concussion Syndrome.




The brain is unique in not having its own nerve supply.  When Penfield did his localisation studies stimulating parts of the brain this did not lead to pain.

The brain however as our control centre, will give all the symptoms that can arise in our lives by effectively the 60 trillion neural connections getting it wrong.


How this matrix of neuronal and neurochemical interactions gets it right most of the time and then fails under certain circumstances, has been the greatest challenge for neuroscientists.


The genetic makeup of the individual is now known to be fundamental.  It would seem that this is the reason why up to 20% of all women get migraine, 40% of whom will have migraine with aura, but 96% of the whole world get headache some time in their life.  Similar arguments apply to the other paroxysmal disorders such as epilepsy and vertigo.


When the brain gets it wrong however, there may be a limited number of symptoms that can reflect a whole range of pathologies through an organic structural neurological perspective.  What then becomes a challenge is that similar symptoms will emerge in the setting of primary psychiatric disorders.  Making sure as psychiatrists, that the organic structural disorders have been excluded is perhaps one of the worrying challenges for modern psychiatry and neuropsychiatry.


For instance depression frequently precedes Alzheimer’s Disease, Parkinson’s Disease and even the horrific Jakob-Creutzfeldt Disease.  Although these conditions may not necessarily lead to medico-legal implications, the same does not apply for sub-frontal meningioma, pituitary tumour, subdural haematoma or hydrocephalus is missed.  All of these conditions can present in a similar way, as can small vessel viva vascular disease and inflammatory diseases of the nervous system such as multiple sclerosis.




Neurologists focus their own thinking on where in the nervous system is a problem taking place.  I suspect the psychiatric model is different.  What we know in neurological practice, is that if you do not focus on where the problem is arising then remarkably thinking can be undermined, investigation wrongly focused and diagnoses missed.  The exceptions to this rule are the disorders such as Parkinson’s Disease which are pattern recognised.

I find that in thinking about this talk that the position for psychiatrists is much the same as it is for pain specialists.  What you want to know is that an individual has no underlying disease or structural process, that needs specific medical or surgical treatment, such that you can focus on the psychological and psychiatric needs of the individual affected.  Pain specialists face the same conundrum and feel quite vulnerable if an individual has not been fully investigated or diagnosed.




Individuals will present with a whole range of psychological, emotional and behavioural symptoms, many of which may reflect brain damage or disease.  It could be argued that if every individual presenting with a psychiatric disorder was scanned, had an EEG and a whole range of blood tests carefully considered according to the individual demographics, then nearly all the conditions discussed today and the vast number that could not be discussed would be excluded.  This would clear the air for psychiatric management to be secure and sleep easy nights guaranteed.




In neurology practice I do not like the “atypical”.  We deal with people for instance who have cluster headache syndrome or trigeminal neuralgia or even multiple sclerosis.  There are very typical presentations and then there are presentations that are not quite typical.


It is this latter group that need particular care, and even though the typicals will need full investigation, it is the atypicals that require a thinking process that is outside the box .  “Have I excluded every possible alternative diagnosis”.  For instance in a disorder like cluster headache which is atypical, does the individual actually have an aneurysm in the retro orbital vascular tree.  Is there a sphenoid sinus mucocele or basal skull pathology?


I suspect a similar thinking applies to psychiatric practice.  Is there anything in the history either by the stability of the family background, the age and sex of the individual, the presence of even the mildest physical symptoms that suggest that the symptoms of apathy, demotivation, sleep disruption, poor appetite and a host of other psychological symptoms could be the manifestation of a structural disease.  For instance is there a bladder dysfunction?  Is the individual unsteady on their feet?  Or do they have any sensory or motor symptoms?  Sometimes it is necessary to ask specifically such as with regard to the special senses.  Learning how to do a competent neurological examination will pay dividends.  Dr Peter Harvey now deceased neurologist, used to give a lecture on the one minute neurological examination.  Sir John Ellis the Dean at The London Hospital when I started medicine said “Know normal – the abnormal will become obvious”.




If there is any degree of suspicion, use the most important neurological instrument, it was invented by Bell.  It saves lives and stops lawsuits.  There is always access to a neurological registrar at the regional centre.  A brief word can save a lot of later explanation and self deprecation.




Nearly every brain disorder can have its neuropsychiatric consequences.


Inherited disorders, acquired disorders, whether they have been neuro-degenerative, vascular, inflammatory, infective, malignant, related to trauma, metabolic or endocrine causes and deficiency disorders will all have a psychiatric presentation to them and many of these will be illustrated in this talk.

The article by Butler & Zeman 2005: 76:i13-i38 covers all of the ground.




There is a grey zone between neurology and psychiatry.  This includes:


  1. Somitisation Disorders

  2. Disassociative  Disorders

  3. Hypochondrias 

  4. Factitious Disorders

  5. Elaboration to convince and deceive


and these will be discussed.




There are obvious disorders such as dementia which will present to the psychiatrist, but being comfortable in separating delirium from dementia is essential, and in the paper mentioned there is a useful table that allows delirium and dementia to be compared.










Slow Progression


Hours – Weeks



Abnormally high or low

Typically normal



Typically Normal



Relatively Normal



Intact in early dementia

Working Memory


Intact in early dementia

Episodic Memory




Disorganised, delusions



Slow/Rapid, Incoherent

Word finding difficulty


Illusions/hallucinations common

Usually intact in early dementia



Varies: often intact early



Most psychiatrists are aware that conditions like systemic lupus may present with a psychosis and multiple sclerosis frequently can generate depression.


What may not be so well known, is the effect that chronic balance disorders even benign paroxysmal positional vertigo, can generate severe anxiety when the diagnosis is either missed or the individual just not believed, when they say that they are constantly dizzy.  Very simple tests can sort this out from the neurological perspective.


Rarer conditions include the group of autoimmune and encephalopathies that can present with a whole range of amnesic and behavioural disorders but usually associated with epilepsy.  These conditions have been clarified since the paper of Butler and Zeman.


Vitamin B12 deficiency, hypo and hyper thyroidism,   pheochromocytoma, carcinoid and a range of other endocrine disorders, even including spontaneous and diabetic treated hypoglycaemia again may generate psychological presentation.




There are a number of relatively unusual neurological syndromes that can generate considerable diagnostic difficulty.  These include the following:


  1. Sub-clinical status epilepsy presenting as a fug state

  2. Narcolepsy with cataplexy.

  3. REM sleep behavioural disorders

  4. Visual Agnosia Syndrome  such as balance and Gerstmann’s Syndrome


A whole range of frontal lobe disorders with executive dysfunction, problems with memory, concentration, attention, planning and multi-tasking.

Perceptual disorders (Charles Bonnet Syndrome).


Mis-identification Syndromes (very rare).


Disorders of practice, where practice is defined as a translation of an idea into action,  including the alien hand syndrome.


Disorders of thought with delusions that may occur for instance in MS, Alzheimer’s Disease and Lupus.


........... Syndrome and balance, Gerstmann’s and Anton Syndrome.


There are also a range of exceptionally rare disorders ,that the writer himself has never actually seen, even allowing for the concept that the definition of a specialist is the individual who has seen the rare twice.



Dr Michael Gross MA MD FRCP MEWI