An introduction to case formulation

One definition of case formulation is ‘Case formulation aims to describe a person’s presenting problems and use theory to make explanatory inferences about causes and maintaining factors that can inform interventions’. What this means is that it is essentially a story not just to describe, but explain, how a person’s problem has developed, and how it is maintained so that treatments can be based on influencing those factors.

There are many different frameworks for case formulation, but several key elements are usually present:

1. a description of the presenting issues;
2. the factors that act to create vulnerability or precipitate the problems developing;
3. factors that may not have been involved in the initial problem developing, but are helping to maintain the problems; and finally,
4. factors that can help the person cope or act as resources.

To move beyond just describing these factors, a case formulation should describe the relationships between these various factors and the problems that are present – and should reflect not just the visible features of the problem (ie what we can see, or what the person reports that are unique to his or her situation), but also the underlying phenomena or stable, recognisable features that are present.

I personally prefer to use Haig’s Abductive Theory of Method (ATOM) for clinical reasoning and formulation.  This is a little bit complex to explain, but I’ll have a go!  For a much fuller description from Fran Vertue and Brian Haig, you really need to go directly to their paper, just published in Journal of Clinical Psychology Vol 64(9).

To quote from their paper, ‘abductive reasoning is a form of inference that takes us from descriptions of data patterns, or better, phenomena, to one or more plausible explanations of those phenomena. This explanatory move is from presumed effect(s) to underlying causal mechanisms; it is not an inductive move to a regularity or law, nor a deductive inference to, or from, observation statements.’

Hmmm, let’s simplify that a little!  Abductive reasoning (AR) infers from patterns that we observe to one or more ‘plausible’ or reasonable explanations for what we see.

What this means clinically is this:

• We start by following a generic interview covering the main areas of interest in an assessment of a person with pain.  The basic information we’re obtaining is specific to that person, and what we find out may well differ from day to day depending on the person and his or her presentation.

• While we’re doing this however, we’re listening carefully for alerts or flags that we know we should explore in more depth. These alerts are based on our knowledge of the literature and past clinical experience – Vertue and Haig call it a ‘database of symptom patterns’.  We’re probably forming a tentative hypothesis about whether this feature is what Haig would call a phenomenon (or pattern that is reasonably stable in this person’s presentation).

Here’s an exmaple:

A person describes no longer participating in usual sporting and social activities while also saying that he or she is worried about moving because of concerns about doing further damage.  The specific statements of ‘I can’t do things’ and ‘I’m worried about doing more damage’ suggest that we should look a little more closely at this aspect of the person’s presentation – like an alert that we should explore in more detail.

If we find more information about this, and identify that the person also catastrophises and/or avoids specific activities, then we are well on our way to describing a phenomenon that we recognise as fairly common, and has been identified in the literature as pain-related anxiety.

BUT to avoid prematurely deciding that this is pain-related anxiety and avoidance, we need to collect some more information from, for example, the PHODA or Tampa Kinesiophobia Scale, and we would probably also want to see the person doing some activities and ask what is going through his or her mind as they are asked.

Identifying the presence of kinesiophobia or pain-related anxiety and avoidance doesn’t, however, necessarily explain all the features of this person’s problem. It can form part of the picture, (or story, really because we’re developing a description!) but it’s not complete, because it doesn’t go far enough to describe the whole of this person’s presentation.

More on this on Monday, this is a fascinating area of theory and practice, and I think it’s under-developed in many fields of health care.

Frances M. Vertue, Brian D. Haig (2008). An abductive perspective on clinical reasoning and case formulation Journal of Clinical Psychology, 64 (9), 1046-1068 DOI: 10.1002/jclp.20504