Pain, 46 (1991) 235

0 1991 Elsevier Science Publishers B.V. 0304-3959/91/$03.50

235

PAIN 01909

Reply to A.R. Block

A.J.M. Schmidt Department of Medical Psychology, Rijksunicersiteit Limburg, 6200 MD Maastricht (The Netherlands)

(Received 9 April 1991, accepted 8 May 1991)

Dear Editor.

Dr. Block states that pain intensity ratings can be viewed as a form of pain behaviour that can be influ- enced by a different set of environmental contingencies than other forms of pain behaviour. I continue to find this an unfortunate interpretation of the concept of pain behaviour. VAS pain ratings do not fulfill the classic definition of pain behaviour, namely: overt ex- pressions of pain and suffering [see for example 1 and 21. Their descriptions of pain behaviour always pertain to spontaneously occurring behaviour of the pain pa- tient which can be observed in (possible experimentally manipulated) situations. This is not true of VAS pain intensity ratings: the patient reports at the request of the researcher or therapist, therefore at a moment that he determines, a number between 0 and 100. I agree with Block that this number will be influenced by factors other than physical sensations. However, it also is true that other dependent variables, such as activity level, verbal or non-verbal complaining or medical con- sumption, refer much more clearly and directly to the essence of what, in my view, is pain behaviour. More- over these variables are much more relevant; behaviour modification is not primarily directed at the reduction of pain.

The research model applied by Block (the presence or absence of solicitous vs. non-solicitous partners as

Correspondence to: Dr. A.J.M. Schmidt, Department of Medical

Psychology, Rijksuniversiteit Limburg, Postbus 616, 6200 MD Maas-

tricht, The Netherlands.

independent variables) is perfectly suitable for studying the influence upon ‘classic’ pain behaviour. Research into this has just been completed by our research team and is being offered to Pain for publication at this time.

Incidentally, I agree with Block’s proposition that both external and internal factors can influence pain behaviour. At the present I would refine my ‘either/or’ approach, criticized by Block. A re-formulation is: in which phase of the progression from acute to longer lasting, chronic pain do the various psychological fac- tors influence or determine the pain behaviour? My hypothesis on this matter is, that in the transition phase from acute to chronic (‘healing time’), operant factors are of great importance. As the complaints last longer, cognitive factors become more important. The patient then refrains from doing something because he is convinced that he cannot do it; it would, for exam- ple, produce too much pain and other complaints. As chronicity continues, automatic behaviours become more important. The patient then refrains from an activity because he simply never performs it or vice versa; for example, when the patient uses medication simply because he does that every day.

References

1 Turk, D.C. and Flor, H., Pain > pain behaviors: the utility and

limitations of the pain behavior construct, Pain, 31 (1987) 277-295.

2 Turk, D.C., Wack, J.T. and Kerns, R.D., An empirical examination

of the ‘pain-behaviour’ construct, J. Behav. Med., 8 (1985) 119-130.