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Knowing what or understanding how:
The role of RCTs in changing
clinical practice
Ivan Eisler
Reader in Family Therapy
Institute of Psychiatry, Kings College London
EFTA/AFT Congress4th - 6th October, 2007.
Glasgow
All who drink this remedy recover in a short time except those whom it does not help who all die.
Therefore it is obvious that it only fails in incurable cases.
Attributed to Galen 2nd century A.D.
Our 2 psychology colleagues maintain that the RCTs all point to CBT and there is little or no RCT research evidence for the value of systems or psychoanalytical family work. Any advice or pointers that you could offer would be appreciated, as my colleagues here and I use psychodynamic and systems approaches because we are committed to them and believe that they work
Smith & Pell 2003 BMJ;327;1459-1461
One of the major weaknesses of observational data is the possibility of bias, including selection bias and reporting bias, which can be obviated largely by using randomised controlled trials. The relevance to the procedure under discussion is that individuals using it are likely to have a high prevalence of pre-existing psychiatric morbidity. Individuals who do not use it are likely to have less psychiatric morbidity and may also differ in key demographic factors, such as income and cigarette use. It follows, therefore, that the apparent protective effect may be merely an example of the “healthy cohort” effect.
Smith & Pell 2003 Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials BMJ;327;1459-1461
One of the major weaknesses of observational data is the possibility of bias, including selection bias and reporting bias, which can be obviated largely by using randomised controlled trials. The relevance to parachute use is that individuals jumping from aircraft without the help of a parachute are likely to have a high prevalence of pre-existing psychiatric morbidity. Individuals who use parachutes are likely to have less psychiatric morbidity and may also differ in key demographic factors, such as income and cigarette use. It follows, therefore, that the apparent protective effect of parachutes may be merely an example of the “healthy cohort” effect.
Debriefing
“the experiences of 700 CISM teams in more than
40,000 debriefings cannot be ignored,
especially so when the overwhelming majority
of reports are extremely positive”
Mitchell & Everly, 2003
Debriefing
• Review of 15 RCTs of single session debriefing
showed no short term difference between
debriefing and control
• 2 RCTs with long term follow-up showed worse
outcome following debriefing (particularly in
those with worse initial trauma)
The development of 'empirically validated treatments'
Open testing of treatment
Randomised clinical trial
Abandon treatment
-ve result
Clinical observations
Theoretical model
Development of new treatment
Adopt treatment as standard
practice
+ve result
Limitations of randomized treatment trials
Subjects selectivity classification dropouts
Nature of treatments restricted nature treatments time limitations common factors
Evaluation of outcome efficacy v effectiveness short term v long term outcome clinical v measurable outcome outcome from whose perspective
The evolution of clinical practice
Conceptualization of therapy and model of change
Explanatory models of disorders
Professional consensus views
Evolution of clinical practice
Clinical practice Randomised clinical trial
Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.
Sackett et al (1996) Evidence based medicine: what it is and what it isn't. BMJ. 312, 71-2,
David Sackett
The practice of EBM means integrating individual clinical expertise with the best available external clinical evidence from systematic research
Sackett et al (1996) Evidence based medicine: what it is and what it isn't. BMJ. 312, 71-2,
David Sackett
Conclusions
• It is important to distinguish the role of evidence in making “categorical” decision and ongoing “process” decisions
• The RCT paradigm provides a useful but limited test of the efficacy of treatments
• RCTs (cumulatively) can have an important effect on professional consensus which influences the allocation of resources, training as well as clinical practice
• RCTs, by limiting clinical autonomy, will often lead to unexpected results which challenge beliefs about mechanisms of change and conceptualization of treatment
• Changes in clinical practice require a change in the understanding of how treatments work which requires a mixture of inductive and deductive reasoning