Psychiatric Formulation Demystified – The Sherlock Holmes Way

A good psychiatric formulation requires sound deductive reasoning. There is no one better than Sherlock Holmes at the art of deductive reasoning.

Deductive reasoning is a form of thinking where you gather facts and develop a hypothesis based on those facts i.e. base your hypothesis only on the facts obtained, not on a pre-existing assumption.

This is in contrast to inductive reasoning where you start off with a hypothesis (or diagnosis) and then look for specific facts that support the hypothesis or arrive at a probable conclusion.

You can see the danger with the latter as you may succumb to confirmation bias overlooking important clues that may lead to an alternate diagnosis and vitally, different treatment.

Deductive reasoning will help you pick up the proverbial zebras when you hear hoofbeats and avoid herd mentality (excuse the pun).

Essentially what you are doing is coming closer to the truth by developing hypotheses based on facts and eliminating or refining them as you go along, all the time ensuring that you are working towards patient recovery.

This ensures that you do not use terms like treatment resistant lightly; rather focus on factors that may be leading to treatment resistance. According to Sherlock Holmes –

Attaching a label such as schizophrenia to a patient is the easy part. The treatment for schizophrenia is antipsychotics and other psychosocial treatments according to evidence-based principles. That’s not too difficult, is it? But what matters is the understanding of the factors that are etiologically and prognostically related to the illness. It is this understanding that will help you make a difference to your patient’s condition. This is where the psychiatric formulation comes in.

The formulation is the integration of patient data, etiological and prognostic factors along with their complex relationships from a biopsychosociocultural- diet lifestyle perspective to develop a coherent management plan. This is somewhat summarised in the foreword in DSM-5;

In fact, if you think of it, you do not necessarily need a diagnosis to relieve distress and enhance psychosocial recovery. A diagnosis is a form of labelling that facilitates communication amongst health professionals. Let me illustrate this as we go along.

Let’s for a moment forget that we had diagnoses. Imagine you had the following patient:
40 year old female living with her mother with psychotic and affective symptoms. The following additional data is obtained on history:

• Family history of psychotic illness
• Obstetric complications
• Epilepsy
• Thyroid dysfunction
• Polycystic Ovarian Syndrome (PCOS)
• Hypertension
• Cognitive dysfunction on frontal lobe examination

This patient is on Valproate, Lithium, Thyroxine, 2 Antipsychotics and 2 Antiepileptics. The patient continues to have distressing symptoms. So how do you treat the individual?

To truly manage the case, you must liberate yourself from the shackles of DSM-V or ICD-10, use deductive reasoning and refrain from jumping to conclusions just because the patient fulfills criteria for a certain disorder.

Break the case down into parts and then attempt to understand how each factor is associated with the condition i.e. devising a formulation is the only way to devise a coherent management plan.

So in the above case, these are the thoughts that should run through your mind helping you devise a formulation; (Note this list is not exhaustive)

• Did you know that epilepsy is associated with psychotic and affective symptoms in 5 different ways (The composite neuropsychiatric hypothesis by Prof Sachdev)?
• Did you know the protopathic bias operating in the association of lithium and Thyroid dysfunction and Valproate and PCOS?
• Did you know that PCOS is part of insulin resistance syndrome and insulin resistance is independently associated with psychotic and affective symptoms?
• Do you know the pharmacokinetic and pharmacodynamic considerations of the medications involved?
• Do you know the neurodevelopmental hypothesis of psychosis and affective symptoms which are associated with treatment resistance?
• What are the cardiovascular risk factors involved in this case will affect response to treatment, psychosocial recovery, and cognition (Vascular hypothesis)
• Did you know that insulin resistance is independently associated with poor cognition?
• Did you know that thyroid dysfunction and especially thyroid antibodies are independently associated with bipolar disorder?
• What are the psychological elements that are preventing recovery?
• Is there high emotional expression playing a part with her living with her mother?
• Is it illness or personality factors that have affected her interpersonal relationships?
• Is the cognitive decline related to illness, side effects of medication or neuroprogression?

I have just outlined a few etiological and consequential elements of the formulation for you to think about. You can see that each question above will lead to a management pathway.

What remains are further consequential components that affect psychosocial recovery and any speculative aspects. You can have a look at this video to see how etiological, consequential and speculative aspects are integrated into a formulation.

All of the above is communicated in short paragraphs in a succinct manner enabling all future management to take place based on an understanding of these basic formulation elements.

There is no assumption of concreteness but provides understanding and vision for the reader/listener.

Compare this to a diagnostic word which unfortunately does not encompass all the necessary nuances that affect this individual.

This is not to say that diagnoses are not useful; they have a place, but one must understand their limitations. They are useful for empirical research and epidemiological purposes, but for good clinical practice, formulation trumps diagnosis any day!

Another important point to remember is that the individual changes constantly so what you saw yesterday might not be the same today as risk factors are fluid and change in nature and direction over the years.

Foreseeability is, thus, important and a diagnosis does not take into account foreseeability or patient goals. I tend to believe

We can’t treat a person cross-sectionally; we must think longitudinally as our ultimate goal is not just reduction of symptoms but helping the individual achieve psycho-social recovery.

The permutations and combinations of the factors affecting an individual’s illness are manifold.

Once you develop a good understanding of the relationships between the various risk factors you divide them into modifiable and non-modifiable elements and start addressing each based on your knowledge of psychopharmacology and psycho-social interventions.

Here are examples of data synthesis.
Bear in mind data synthesis is not just a regurgitation of the history in a succinct manner, it is the integration and synthesis of the data obtained based on deductive reasoning.

23 year old female with mood disorder and personality traits suggestive of borderline personality. As you can see, both biological and psychological elements are playing a part.

“From a biological point of view, there is a genetic predisposition towards developing a mood disorder. Her mother had been treated for depression and her father for anxiety. There is also a family history of suicide on the mother’s side.

Additional biological contributors to be ruled out include thyroid dysfunction, polycystic ovarian syndrome both of which are known to be associated with borderline type presentations. Her PCOS may also be associated with her weight issues due to insulin resistance and will need to be taken into consideration if psychotropics such as antipsychotics or valproate are prescribed.

From a psychological point of view, an important theme that arises is that although there is no significant physical abuse, sexual abuse or emotional abuse, and overall the family is very supportive, X did have a significant period of perceived neglect during her early childhood as her parents had to care for her younger brother who has severe intellectual disability.

When asked this particular question, X was tearful which is possibly indicative of her loss and perceived neglect that would have led to attachment difficulties during early childhood.

These attachment difficulties would have led to not only dysfunctional assumptions of self but also emotional dysregulation through interference of neurodevelopment particularly of the parasympathetic and sympathetic nervous system, (Sarkar and Adshead, Advances in Psychiatric Treatment) which would explain her mood dysregulation.

She can be also be conceptualised along the dialectical behavioural model whereby her emotionally invalidating environment during early childhood along with her underlying biological predisposition has led to pervasive emotional dysregulation as evidenced by her mood symptoms along with recklessness, impulsivity and trust issues.

Her predominant ways of coping during this early phase of life was through externalising behaviours of recklessness, impulsivity and “getting into the wrong crowd”.

She also had a period of shop-lifting and got into trouble with the police because of that. These rebellious behaviours were predominant coping mechanisms for her during this difficult phase of adolescence. She, nonetheless, is quite insightful about these issues and seems to recognise that these were maladaptive.

Self-harm has been used as self-soothing mechanism as well, obtaining relief after self-harm episodes.

I am mindful of the impact of personality traits on my therapeutic relationship with her, and it is likely feelings of abandonment and mistrust, along with a heightened sensitivity to rejection will need to be addressed carefully along with the use of primitive defences such as splitting, idealization and denigration and acting out.

Fortunately, she does have a supportive family, has good insight and a motivation to get better which are all positive prognostic factors”.(There are additional psychological models that apply here, that can be presented succinctly such as the CBT model and the schema based model. You must, however, be confident about how you envisage these to work and if they fit this particular case)

A 53-year-old male referred for depression. This formulation led to an MRI being carried out and moderate parietal lobe atrophy identified. Medication changes via a specialised unit led to complete resolution of the symptoms and improvement of depression.

This formulation is a good example of how once you gather all the facts, what looks like depression isn’t straightforward depression (the horse being a zebra although was referred for hoof beats). The data was integrated, and the direction of causality was examined carefully. Here is an excerpt from the formulation.

“From a biological point of view, there is a genetic predisposition towards developing what seems to be an REM sleep movement disorder.

The presence of a strong family history across all generations in males raises the possibility of an autosomal dominant condition. The restless legs syndrome may be present along with periodic limb movement disorder. Restless legs syndrome itself is also inherited in an autosomal dominant fashion.

The importance of REM sleep movement disorder is that it is often associated with disorders of the basal ganglia such as parkinsonism, multisystem atrophy or other basal ganglia afflictions which need to be ruled out. (synucleopathies)

There were no other features of parkinsonism identified on examination, such as cogwheel rigidity, pill-rolling tremor; however, I did notice his stooping gait and slowness of movement, however, I am uncertain whether this is a pre-existing condition.

The onset of a psychiatric disorder at the age of 50 raises the possibility of a primary organic disease unless proven otherwise. Moreover his psychiatric symptoms are most likely secondary to a primary neurological disorder and thus organic investigations are needed to rule this out.

The amphetamine use is associated with sub-cortical deficits and may present with such a picture as is an inflammatory illness associated with Hep C ……………and it goes on to cover additional elements”.

This would be followed by psychological elements (e.g. adjustment, cognitive impact, etc.)…..which are not covered here but you get the picture.

1.  Explore, do not assume – Hypothesis Based Interview
2.  Synthesise and generate hypotheses – Formulation Matrix
3.  Strategise and implement – Strategic Decision Making Paradigm

Your formulation whether in private or public practice is your most powerful clinical tool and showcases your thinking process to anyone reading or listening to it. It is an invaluable skill that will surely be tested in the real world.

Click here to watch the video – How to Develop a Psychiatric Formulation and Management Plan by Dr. Sanil Rege.