1. OCD Research in the Lab: A Research Pathway for Psychological Models
Graham C L Davey
University of Sussex, UK

5. Purpose
To make explicit the need to address the external validity of developed models of OCD
To provide a clear programme of research to extend research on healthy individuals to diagnostic populations
To recommend a closer reciprocal relationship between models of OCD and existing core psychological knowledge

6. What is Experimental Psychopathology
The study of psychopathology processes under highly controlled conditions
To develop detailed models of psychopathology
EP is often carried out on healthy humans and nonhuman animals
Has been significant in furthering animal models of psychopathology and pharmacological treatments

7. Neglected Issues in Experimental Psychopathology
A Pathway of EP Research in developing psychological models of psychopathology is unclear
Biological and psychological models have often developed in parallel rather than collaboratively
Psychological models should offer a broader perspective by integrating cognitive, behavioural & social factors into single etiological models

8. Problems in the Elaboration of Psychological Models
Psychological models have often developed chaotically and independently of each other
Psychological models are often driven by clinical experience rather than core psychological knowledge
There is a preponderance of esoteric constructs – especially in OCD research
The role of research on healthy individuals has been consistently undervalued
There are fewer and fewer outlets for EP research on healthy individuals
EP researchers have often been negligent in ensuring the validity of their research to clinical populations

9. Bridging the Theoretical Gap Between Laboratory Studies & Clinical Populations
No need to question the research skills of well-trained empirical researchers
It is external validity that is often overlooked
Using external validity criteria to validate translational research

10. External Validity Criteria
Validity Criterion
Definition
Face Validity
The phenomenological similarity between the behaviour in the laboratory model and the symptoms of the disorder
Predictive Validity
Performance in the laboratory model predicts performance in the disorder
Construct Validity
The model developed in the laboratory can be compared favourably with existing clinical models of the disorder. The processes described in the laboratory model parallel the clinical processes of interest
Aetiological Validity
It can be shown that the aetiologies in the laboratory model and the disorder are identical (this is very similar to construct validity)
Convergent Validity
The degree to which outcomes from the laboratory model correlate with measures/outcomes from other models of the same disorder/construct
Discriminant Validity
A model differs from other models of the same disorder to the extent that it’s outcomes are different to those predicted by other models
Diagnostic Validity
Demonstrating that the laboratory model taps into processes that are unique to the clinical population exhibiting the disorder

11. Face Validity Weakest Criterion but Often a Starting Point
Formalistic similarity between the behaviour in the lab and the symptoms in the disorder
Measuring ‘symptoms’ in an analogue task (e.g. checking)

12. Predictive Validity
Your laboratory model predicts behaviour in the disorder
Manipulating critical variables in your model and showing they affect symptoms (e.g. manipulating ‘inflated responsibility’)
BUT – is the behaviour in your model and the behaviour in the disorder generated by similar mechanisms?

13. Construct Validity
Requires that the laboratory model compares favourably with a clinical model of the disorder
Causal processes in your model can also be identified when those processes are examined in the clinical population
Processes in the laboratory model can also be identified in clinical populations through etiological case histories (e.g. Davey, de Jong & Tallis, 1993)
Benefit of the laboratory model is that it can be used to explore further implications of the model for the disorder

14. Diagnostic Validity
Requires that the researcher should be able to demonstrate that the laboratory model taps into processes or characteristics that are unique to the clinical population (Vervliet & Raes, 2013)
Clinical populations may possess characteristics that make them highly vulnerable to the model
Extends the model to identifying psychological markers of vulnerability for psychopathology

15. A Research Pathway for Experimental Psychopathology
Does your model superficially look like the clinical phenomenon?
Does your model predict what happens in the clinical phenomenon?
Can you show that the processes in your model closely resemble the processes in the clinical phenomenon?
Does your model explain why the relevant clinical population is differentially vulnerable to the disorder?

16. A 3-Stage Research Pathway for Experimental Psychopathology
Face Validity
Predictive/Construct Validity
Diagnostic Validity
Validity Questions
“Does your model produce measurable behavioural/physiological/cognitive outcomes that resemble the clinical phenomenon?”
“Does your model predict what happens in the clinical phenomenon?”
“Does your model explain why the relevant clinical population is differentially vulnerable to the clinical disorder?”
Participant
Mainly healthy participants
Healthy participants or clinical populations
Clinical populations or healthy participants

17. Stage 1
The adaptation of core knowledge from other areas of psychology to explain the clinical phenomenon
The use of basic experiments under highly controlled conditions to identify causal relationships
To use experimental procedures to ‘infer’ the existence of processes that cannot be directly observed

18. Mood-as-Input & Perseverative Checking
Current mood is used as information in decisions to terminate or continue a checking task
Mood-as-input is a psychological mechanism first developed in the social psychology literature
Can be applied to any perseverative task

19. MacDonald & Davey (2005)

20. Stage 1
Proof of concept stage

21. Stage 1 as the ‘Proof of Concept’ Stage - Disgust & Religiosity

22. Stage 2
Testing predictions of the model against knowledge of what happens in the clinical population
Testing clinical participants to determine whether the variables in the model are relevant in causing or maintaining symptoms
Examining case histories for evidence of the critical processes in the model
Investigating aetiologies of clinical populations using self-report questions and surveys

23. Lopatka & Rachman (1995)

24. Stage 3
What is it about the relevant clinical population that makes them differentially vulnerable to the disorder?
Literature Reviews
Meta-analyses
Evidence that shows the clinical population is significantly more reactive or sensitive to the model’s processes than healthy control participants
Comparing healthy individuals sub-clinical populations who score high on symptom measures
Manipulating the critical variables in healthy participants to a level where they resemble those in the clinical population (especially if the disorder is a dimensional one such as OCD)

25. Susceptibility to Mood as Information Effects in the Anxiety Disorders
Vulnerable individuals have poor problem-solving confidence and decision-making processes
Mood is used as information when the individual is aware that it’s a relevant feature of the current task (as in attempts to repair anxious mood)
Anxiety inflicts a high cognitive load and depletes working memory capacity – in such situations mood is more likely to be used as information

26. Implications of the Research Pathway
You can start at any of the 3 stages!
It would in principle be possible to answer validity questions at all three stages using entirely healthy individuals
Research at each stage is valid in it’s own right
Journal Editors & Funding Bodies should NOT:
ask researchers at Stage 1 to provide evidence that their model is relevant to clinical populations
Insist that research is only clinically valid if it is done on clinical populations