A comparison of primary dysmenorrhoea and intrauterine device related pain

265 Pain, 3 (1977)265"276 © Elsevier/North-Holland Biomedical Press

A COMPARISON OF PRIMARY DYSMENORRHOEA AND I ~ R A I Y r E R I N E DEV][CE RELATED PAIN

A,E. R E A D I N G

and J.R.N E W T O N

Departments of Psychological Medicine and Obstetrics and Gynaecology, King's College Hospital, Denmark- HiU, Le~'~don SE5 (Great Britain)

(Accepted October 27th, 1975)

SUMMARY

A pain :questionnaire designed to measure sensory, affective, evMuative and temporal::componen~ of pain was administered to 119 patients with primary dysmenorrhoea and 75 patients with intrauterine de,rice (IUD) r e l a t ~ i p ~ . :In addition "self-report" information was obtained on the b e h a v i o ~ effects of pain, global ratings and biographical details of these patients. It was found that dysmenorrhoea and IUD related pain were generally similar in natUre, This led to the conclusion that IUD inse~ion does not in general lead to an exacerbation of presenting dysmenorrhoea, nor does it radically alter the type of sensations experienced by the patient. While no differences between patient groups emerged, the implications of the different pain components did vary. Thus, pain intensity scores were reflected in a larger sensory component with IUD users, whereas with dysmenorrhoea the affective c o m p o n e n t predominated. ~ e ; results i show sufficient consensus in the two patient groups of word adjectives u ~ : to describe t h e i r p ~ , t o allow the development ~md ev~uation of a rapid card sort system for pain assessment.

INTRODUCTION

Pain is a common presenting complaint in a gynaecology clinic. In many cases it is appropriate to regard this as a problem in its own right rather than a s a symptom or sign of underlying pathology, as is generally the case in other branches of:medicine. Both pain associa~ed with an intrauterine device ( I U D ) and p r i m a r y dysmenorrhoea -- an exceedingly common complaint -fulfill this description. Studies have shown a variable incidence of dysmenor~hoea ranging from 13 to 31% of women [2] although it is still the largest cause of absenteeism

266 from work or play in the USA [].1]. Many young women have to take time off work and reports indicate a lowered mental performance at the time of dysmenorrhoea, e.g. schoolgirls ta~.-irg exams [4 ]. Similarly, IUD use leads to pain for some women and is a major reason f o r IUD discontint,.ation. According to the Pop~flation Report [ 9 ] removal rates for pain and bleeding, where they were available as a rate apart from other medical reasons, range from 4.0 tO 14.0/~_00 users. There is littie information on pain in this situation beyond the simple reporting of "~fild, moderate or severe". This is inadequate in the light of recent research findings which indicate the importance of discarding a unidimensional mcdei of pain with i~s assumption of a one-to-one relationship between stimulus intensity and pain experience. It appears that a multidimensional concept of pain provides the most complete account [8]. A prerequisite to the effective management of pain is an understanding of its nature and controlling variables. One important question with IUD related pain and primary dysmenorrhoea is their degree of similarity. There is little current information about this point. In the context of a multidimensional concept of pain, a compmfison of the relative importance of different dimensions between groups becomes possible. Three main components of pain have been described --sensory, affective and evaluative [7]. This paper presents the results of a survey evaluating the respective quality and intensity of IUD related pain and primary,dysmenorrhoea and a comparison of the two in order to establiish their exact relationship. It constitutes the first stage in an ongoing study aimed at developing and evaluating alternative methods of pain assessment and therapy for pain relief. METHOD

A modified form of Melzack's Pain Questionnaire [8] was distributed to Caucasian women attending King's College Hospital's family planning and gynaecological clinics. The criteria for inclusion was that they were experiencing pain or had experienced pain in 'tlhe recent past. This pain should have been related to either IUDs or to menstruation. The questionnaires were administered by research nurses in the clinics. The questionnaire consisted of a list of words (from Melzack [8] see Table I) describing pain. Patients were asked to circle words which described the pain that they had experienced. Space: was provided for the inclusion of additional words, A 5-pointed scale was also provided on which patients were asked to rate the pain at its worst, as well as worst headache, toothache and stomach ache (a;~chor po}nts). A body silhouette was included in order to ensure that the patients' pain was located in the pelvic region. Additional questions concerned the effect of the pain on behaviour. Thus patients were asked to indicate "yes" or "~_~o"as to whether the pain usually required pain killers, staying a~ home, avoiding socia]~ activities or going to bed. Space was also provided for the research nurse to report biographical details--age, parity, ethnic ~ e u p and category of pain.

These questionnaires *vverecompleted by I.19 C~casian primary dysmenorrhoea and 75 with IUD related pain,. RESULTS

patients with

.

The word checklists were divided into 4 categories for scoring purposes (see Table I) These were, .words indicating senscry properties of pain, groups TABLE I LIST OF PAIN ADJECTIVES PART A 1 Flickering Quivering Pulsing Throbbing Beating Pounding 5 Pinching Pressing Gnawing Cramping Crushing 9 Dull Sore Hurting Aching Heavy

(after Melzack

[ 81)

2 Jumping Flashing Shooting

3 Prii.;king Boring Drilling Stabbing Lancinating

6 Tugging Pulling Wrenching

7 Hot Burning Scalding Searing

8 Tingling Itchy Smarting Stinging

10

11 Tiring Exhausting

12 Sickening Suffocating

Tender Taut Rasping Splitting

4

SlWP

Cutting Lacer.r.ting

13 Fearful Frightful Terrifying

14 Punishing Gruelling Cruel Vicious Killing

15 Wretched Blinding

16 Annoying Troublesome Miserable Intense Unbearable

17 Spreading Radiating Penetrating Piercing

18 Tight Numb Drawing Squeezing Tearing

19 Cool Cold Freezing

20 Nagging Nauseating Agonising Dreadful Torturing

PART B. How does your pain changt with tfme.? Which word or words would ycm use to described t!le Patfern of yaw pairr? 1

2

Continuous Steady Constant

Rhythmic Periodic Intermittent

3 Brief Momentary Transient

_-,.

yII_“..<-.I-

268

1--10, 17, 18 and 19: words indicating affective properties of pain (groups 11--15 and 20), words indicating the evaluative properties of pain (group i 6 ) , and the temporal properties of p~dn by the groups of words in part B of Table I. Scores were assigned to each category on the basis of the total number of words checked and the summated rank order scores for each word within each category (after Melzack [ 8 ]). A summary of the means and standard deviations of the number of words checked and rank scores by categories, as well as the means of anchor scales is presented in Table II. The space provided for additional words to describe pain was used in only one case, that being a patient in the IUD group who included the description, "like period pains". -The scores on each dimension were compared by double-tailed " t " tests and no significant differences found. Inspection of Table II shows that the mean intensity of the two types of pain was similar, all mean values between 3.0 and 4.0. The mean number of words checked by category was also similar between the two groups. A greater number of sensory words as compared with affective and evaluative words wa~ c h e c k e d b y both patient groups. The age cistribution within the two patient groups is presented in Table III. In the d~tsmenorrhoea group 37 were nulliparous and 18 had been pregnant. For ILD re~ated pain, 19 were nulliparous and 14 had been pregnant. The numt~ers of women within each group declaring the use of pain kiP ers, stayblg at home, avoiding sociat activities or going to bed is presented in Table IV. These figures are shown as a function of the pain intensity scores in Table V. Chi Square tests of association were calculated both within and between the patient gr,~ups. The use of pain killers was related to pain intensity scores within both ~ ~ups (IUD, X 2 = 12.7, d f = 4, P < 0.01; Dys, X 2 = 9.37, d f = 4., P < 0.05). Thus, the more severe the pain the more likely it was for pain killers to be taken. No significant associations were found in the IUD group between pa!a intensity and staying at home or avoidir,.g social activities, although t~e association with "going to bed" approached significance (X 2 = 7.32, d f = 3, P < 0.06). None of these variables were significantly associated in the dysmenorrhoea groups. Owing ,,o small numbers within cells, parity was dichotomised in nuUiparous m.d multiparous women and compared with pain intensity, taking pain kiil~rs, staying home, avoiding social activities and going to bed. No sign'Ficant association was found for either group. The temporal quality of the pain was divided into brief, period or continuou,z. A significant association wa~ found within the IUD group between parity and temporal quality ~×2= 6.-16, d [ = 2, P < 0.05). Multipazous women repot'ted pain of a more continuaus nature, while nulliparous tended to describe their pain as intermittent. A X: test was computed for the number of words checked (NWC), see Table H, by category, by breaking the number of words checked into 3 g~oups for sensory and affective categories and two groups for the evaluative category. No significant association was found between NWC by category

Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhsea IUD Dysmen0rrhoea IUD

Pain intensity

sensory category Rank order sc~lres for the affective category fcr the ‘@nk order SCCPTP-” __ evaiuative category _______II -_..“._ __ __---

Rank order scores for the

Total numbers of words checked (78) I++Iumber of words checked from the sensory category (54) Number of words checked from the affective category (19) Number of words checked from the evaluative category (5) ank of order scores for total

Stem ach ache

Headache

Toothache

Patient group

Pain measure

SUMMARY STATISTICS FOR BOTH PATIENT GROUPS

TABLE II

72 110 106 70 106 70 106 70 146 73 118 69 119 75 119 75 111 69 111 65 418 75 118 V n d-x -_-

N

3.52 3.61 3.29 3.32 3.79 3.35 3.52 3.87 6.77 7.16 4.77 5.11 2‘11 2.37 1.61 2.04 18.3 17.6 13.5 13.9 3.14 3.i4 3.11 3.09

Mean

1.49 1.28 1.11 1.18 1.25 1.00 9.53 11.65 9.04 11.7 9.09 11.4 9.08 11.37 15.5 15.4 13.6 11.1 9.8 -I* II.Ur? 9.6 11.5

l-l? &..a..

1.19

Standard deviation

NS NS

0.17 0.29

NS NS

-0.02

NS 00

0.20

NS

NS

0.23

-0.29

NS

NS

-I..-c

Significant

0.26

-0.52

t

?i?

a2

270 ‘FABLE

III

AGE DISTRIBUTION Patient

group

WITI-IIN PATIENT

GROUPS

Age

Dysmenorrhoea IhlD

15-20

21-25

26-30

31-35

35+

15 3

16 9

13 13

7 3

4 1

and the use of pain kil!lers for either group. Pain intensity was significantly associated both with the number of words checked from the sensory category (NWC-S) and from the evaluative category (NWC-E) in the IUD group (x2 = 15.7, df= 8, p<: 0.05; x2 = 15.5, df = 4, P< 0.01). Women who checked more than one of the 5 evaluative words were more likely to rate their pain at maximum intensity. Within the dysmenorrhoea group the number of

werds checked in the affective and evaluative categories was significantly associated with pain intensity (x2 = 17.0, df = 8, P< 0.35; x2 = 9.8, df = 4, p<

0.05). A further

NWC-E with use of pain killers, age and parity, NWC-E scores were dichotomised into patients who checkec? no words at all, and those that checked one or more. Within the TJD group the analysis

compared

ellaluative category was not used by 33 of the 75 women in the sample. This compares with a to&a! of 52 in the dysmenorrhoea group. Neither age nor parity were significantly associated in either group with the NW&E. Use of pain killers was associated significantly with NWC-E in the IUD group (x2 = 3.59, df = II9 P < CM), and approached significant levels in the dysmenor-

rhoea groiap (x2 = 2.47, df = 1, P < 0.1). A Pearson corre’lation analysis was performed on continuous data for both groups aqd is presented in Table VI. Neither age nor parity correlated significantly with any of the pain measures. Pain intensity scores correlated significantly with NWC in the IUD group and approached significance in the dysmenorrhoea oup. h both groups, toothache and headache were correlated, but not with pain intensity. Pain intensity was correlated however, with

BEHAVIOURAL Figures in brackets Patient

group

EFFECTS indicate

OF PAIN WITHIN PATIEKT the total patients

Behavioural

respsnses

GROUPS

within each cell. Cs pain _

Take pain l$ler

Stay at home

Avoid social a&iTzitiles

Go to bed

87 (108) 54 (71)

23 (55) 1.0 (29)

39 (5%) 20 (29)

25 155) 14 (29)

Yes No Yes No Yes No Yes No

Take pain killers

Go to bed

Avoid social activities

Stay at h o m e

Response, yes or no

Pain b e h a v i o u r

Dys

IUD 0 1 0 0 0 0 0 0

Dys 0 2 ! 1 1 1 0 2

11 5 2 4 2 4 2 4

2

1

6 10 1 7 3 5 1 7

IUD 25 11 7 15 9 13 8 6

Dys

3

Pain intensity scores by patient group

14 8 1 7 6 2 2 8

IUD

16 6 3 8 8 3 3 8

Dys

4

8 2 1 1 2 0 2 0

IUD

28 4 9 5 9 5 8 6

Dys

5

B E H A V I O U R A L E F F E C T S OF P A I N AS A F U N C T I O N OF R A T E D P A I N I N T E N S I T Y WITHIN P A T I E N T G R O U P S

TABLE V

19 3 5 6 7 4 6 5

IUD

b.a

272 TABLE VI CORRELATION COEFFICIENTS BETWEEN PAIN IvlEASURES FOR BOTH P A T I E N T GROUPS Group

Age

PariW

Pain intensity

Toothache Headache

ache .

Age Parity Pain intensity Toothache Headache Stomach ache NWC-T NWC-S NWC-A NWC-E Rank T Rank S Rar,k A Rank E

Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmennrrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD Dysmenorrhoea IUD

0.41 ** 0.28

0.13 --0.08 --0.14 --0.10

Stomach

--~0.05 --~.04 --0.11 0.01 0.03 --0.06

.

.

.

.

"

r

0.04 0.09 0.26 0.14 0.12 --0.13 0.33 ** 0.32 **

--0.01 --0.16 0.00 --0.04 --0.30 0.31 0.23 0.34 0.21 0.18

Two-tailed significance levels, * P < 0.05, ** F ,: ~.01.

storaacb pain. 'the NWC and rank scores were highly correlated ( P / . 0.001) which led to the exclusion of rank scores h'om further analyses. Finally, groups were corapared in terms of the use of pain killers, pain intensity, NWC by category and staying a.t home, and the effects of pain on social behaviour. No significant associations were found between the patient ~:coups in terms of 0ari~y, the use of pair~ killers, or the disruption of ongoing b ehavlour " caused by pain. There was a significant association between p a t i e n t groups and the temporal quality of the pain (X 2= 7.09, d f = 2, P < 0.05). Women i:.~ the d.vsmenon-hoea group were more likely to describe their pain as continuous, arid women in the iUD group as intermittent. No significant associations were found between patient groups in terms of pain intensity scores or NWC by category scoreJ~.

** ** ** ** *

27'3 .

NWC-T .

.

._

..,

NWC-A

NWC-S .

.

.

-0.14 --0.16 --0.17 --9.01 0.20 * 0.52 ** 0.14 * 0.10 0.15 --0.15 0.14 0.18

.

-

-

::

,

. - ) -

.

_

Rank T

Rank S

Rank A

Rank E

"-0.23 ---0.13 "-0,21 0.04 0.13 0.42 0.12 --0.06 0.12 --0.10 0.11 0.09 0.92 0.94 0,97 0.98 0.98 0.99

--0.14 --0.20 0.25 --0.I0 0.31 ** 0.44 ** 0.12 "-0.08 0.16 --0.11 0.10 0.05 0.76 ** 0.86 ** 0.64 ** 0.82 ** 0.60 ** 0.71 ** 0.58 ** 0.67 **

--0.05 "0.20 --0.26 --0.08 0.28 0.34 0.08 0.12 --0.14 ---0.05 0.15 0.04 0.91 0.93 0.86 0.91 0.79 0.82 0.77 0.79 0.87 0.94

--0.21 --0.14 --0.17 0.41 0.19 0.46 ** 0.13 0.08 0.11 --0.14 0.09 0.14 0.94 ** 0.97 ** 0.92 ** 0.97 ** 0.94 ** 0.98 ** 0.93 ** 0.96 ** 0.77 ** 0.77 ** 0.84 ** 0.84 **

--0.06 --0.13 --0.19 0.39 0.18 0.40 0.15 --0.00 0.12 --0.17 0.13 0.08 0.92 0.96 0.92 0.97 0.94 0.98 0.96 0.98 0.72 0.73 0.79 6.82 0.96 0.96

.

- . .

-0:05 --0.14 --0.17 "-0.01 0.15 0.40 ** 0.11 0.01 0.13 --0.33 0.14 0.00 0.97 ** 0,99 ** -

NWC-E

--0.21 "--0.13 --0.08 • 0.03 0.15 0.47 ** 0.12 0.I0 0.11 --0.12 0.11 0.25 0.45 ** 0.96 ** 0.97 **= 0.98 **

**

** ** ** ** ** **

** **

** ** ** ** ** ** ** ** ** **

**

** ** ** ** ** ** ** ** *'~ ** ** ** ** **

DISCUSSION The respective contributions of the different components of IUD related pain and dysmenorrhoea have been compared in order to establish their degree of similarity. This an~ysis draws on a multidimensional model of pain w h i c h a l l o w s f o r t h e f a c t t h a t t h e s a m e s e n s o r y i n p u t m a y give ~ s e t o d i f f e r e n t s u b j e c t i v e : level;; o f p a i n a c c o r d i n g t o s e v e r a l f a c t o r s . T h i s is ~he c a s e w i t h o t h e r p e r c e p t u a l e ' , : p e r i e n c e s ; w h e r e d i f f e r e n c e s also a r i s e ir~ t h e r a t i n g o f ~:he s a m e s e n s o r y i n p u t as a f u n c t i o n o f p s y c h o l o g i c a l f a c t o r ~ . F~>r e x a m p l e , B r u n e r and G o o d m a n [3] s h o w e d size p e r c e p t i o n to be affected by t h e value o f t h e o b j e c t ( c o i n s ) t o b e j u d g e d as w e l l as t h e n e e d f o r it o n t h e par~, o f ~he j u d g e . A m o n g t h e p s y c h o l o g i c a l f a c t o r s c o n t r i b u t i n g t o t h e level o f p a i n

274

experienced are mood. anxiety, cultural belief, focus ef attention and personality [ 10 ]. In the present analysis neither age nor parity were found to be associated with pain measures, with the one exception of multiparous IUD users reporting pain of a more continuous nature. The pain experienced by these two groups of patients (IUD users and dysmenorrhoea) m a y differ quantitatively, qualitatively or there m a y be no difference. These 3 possibilities will now be discussed.

(1) Quarttitative differences This study shows that there is little difference between the degree of pain in each group. Both types of pain were rated at a similar intensity on the s.nchor p-~int scale. A comparison of the number of words checked by category also showed no difference between the two patient groups. Both patient groups checked more than twice as many words from the sensory ca~egory than froth the affective and evaluative categories. An analysis of the rank order score.,: of words checked by category and for the total also reveated no diffeJ'euces between groups. The only significant differences to arise concerned the temporal quality of the pain. Dysmenorrhoea was associated with descriptions indicating a continuous pain, while IUD related pain was associated with words ~uggesting an intermittent temporal quality. Few women in either group reported their pain to be brie~ or momentary. No significant ¢ifferences were found b e t w e e n groups in terms of behavioural reaction,s to pain. Thus, neither group was more likely to use pain killers, stay a~ home, avoid social activities or go to bed as a result of the pain, although approximately 50% of respondents in b o t h groups indicated that the pain dsually forced them to stay at home, avoid social activities or go to bed. A higher proportion within each group indicated the use of pain ld!!ers (71% and 80% for IUD and dysmenorrhoea respectively). These figures testiI!y to the disruption and seriousness of these conditions for a proportion of women. The use of pain killers was significantly associated with the rated pain intensiity within bol~h groups. In other words w o m e n reporting theie pain to be intense on the rating scale were likely to report the use of pain killers. This can be seen as providing indirect support for Beecher:s [ 1 ] conclusion that recording analgesic medication constitutes one of the ,more reliable and valid pain assessment methods available to date. Pain intensity was not significantly associated with other behavioural measur~.s of pain. The pain experienced by these two patien'~ groups was compared with other c o m m o n l y experienced pains {headache, toothache and stomach ache). Our results indicate similar intensity ratings for all these pains. This comparison was able to establish that these pain~ were rated independently as opposed to the scores reflecting a general response set. This conclusion is based on the fact that neither IUD related pain nor dysmenorrhoea was correlated with t o o t h a c h e or headache.

275

(2) Qualitative &!fferences The second p c~ssibility is t h a t the IUD related pain and d y s m e n o r r h o e a differ "in k i n d " .... in o t h e r w o r d s IUD insertion changes the kind of pain that m a y have been previously experienced at menstruation. For example, it was hypothesised t h a t d y s m e n o r r h o e a would have a significant ai!fective and evaluative compc,nent owing to the influence of culture, upbringing and attitudes [6]. By contrast IUD related pain waa expected to have a more p r o m i n e n t sensory c o m p o n e n t owing to ~.;he IUD constituting a tangible pain stimulus giving rise to painful sensations. Moreover:. smaller affective and evalaative scores were expected for IUD pain, owing to the fact that w o m e n have chosen them as a preferred m e t h o d of contraception. In this respect, IUDs have positive benefits to set against the pain. It was expected that dysmenorr h o e a would give rise to greater distress owing to its unavoidable nat~re. Support for t h e c o m p o n e n t s of pain being i n d e p e n d e n t l y conl~roUed by a n u m b e r of psychological factors was found in a s t u d y by Johnson and Rice [5]. Separate ra~ing scales were used to measure ser,,sation and distress c o m p o n e n t s of pain. They found only distress ratings to be affected by ethnic origin. This suggests that equivalent levels of sensory input were responded to and appraised in different ways as a function of cultural background. The expectation t h a t IUD related pain would give rise to the selection of a greater p r o p o r t i o n of words from the sensory category was not confirmed. While no differences were found between patient groups in terms of the n u m b e r of words chosen by catego~y, differences did emerge in terms of the association between the n u m b e r of words chosen and pain intensity scores. The n u m b e r of words checked from the evaluative category was relat.ed to pain intensity for b o t h patient groups. However, within the IUD patient group words checked from the sensory category were also related to p ~.in i~teP.sity, whereas in d y s m e n o r r h o e a words from the affective category were retatecl to pain intensity. This indicates t h a t the n u m b e r of sensory wo.:ds checked by IUD users was associated with pain intensity. For w o m e n with d y s m e n o r r h o e a the n u m b e r of affective w o r d s - in o t h e r words the distress or emotional react i o n - was associated with pain intensity. In other words whereas comparison of the groups as a whole showed no overall differences, the relationship b e t w e e n measures within groups provides some indirect support for the hypothesis cop.cer-ing the relative prominence of sensory and affect;ire categories, it appears that w o m e n with severe d y s m e n o r r h o e a report more affective wcrds, while IUD users with severe pain report a greater n u m b e r of sensory wor is.

(3) No difference in pain between IUD users and dysrnenorrhoea This conclusion is supported by our data with respect to p~':in intensil, y and quality. It also shows that insertion of an IUD does not lead in general to an exacerbation of presenting d y s m e n o r r h o e a , nor does it radicaV~y alter t h e t y p e of pain sensations experienced by the patient. This survey has p~c,vided i n form ation on the types of pain which are

276 experienced by these two groups of patients. This will form the basis of a new method of pain evaluation b ~ e d on our finding o f consensus o f words usec to describe these pains (both meaning and intensity). It wiU take the form of a card sort which provides for a rapid measurement o f a n u m b e r of dimensions of pain, which can be repeated at frequent intervals. : REFERENCES I Beecher, H.K., The measurement of pain in man. In: A. Soulairec et al. (Eds.), Pain: Proceedings of the International Symposium on Pain, Academic Press, New York, !968, pp. 207--228. 2 Be:gsj~b, P., Jennsen, H. and Zellar, O.D., Acta obstet, gynec, scand., 54 (1975) 355--360 3 Btuner, J.S. and Goodman, C.C., J. abnorm. Soc. Psychol., 42 (1947) 33--44. 4 Dalton~ K., The Premenstrua!. Syndrome, Thomas, Springfield, Ill., 1964. 5 Johnson, J.E. and Rice, V.H., Nursing Re.,;., 23 (1974) 203--209. 6 ].'.,,eske, R.K. and Koeske, E.F., J. Pets. Soc. Psychol., 31 (1975) 473--478. 7 l~elzack, R., The Puzzle of Pain, Penguin, London, 1973. 8 Melzack, R., The McGill Pain Questionnaire: major properties and scoring methods, Pain, 1 (1975) 277--299. c Population Reports, Series B, No. 2 (1975) January. i. Rachman, S. and Phillips. C., Psychology and Medicine, Temple Smith, London, 1975. I ii S]oan, D., Pediat. Clin. N. l~mer., 19 (1972) 669--680.