Br. J . med. Psychol. (1975), 48, 49-53 Printed in Great Britain
49
Measures of sleep disturbance in psychiatric patients BY DAVID G. McDONALD* AND ELIZABETH A. KING? Attempts to measure sleep disturbance have appeared in the literature for quite some time, the first report to the authors’ knowledge dating back 40 years. Measurements in these reports have included subjective reports from subjects, often by means of a questionnaire, as well as more objective methods (Johns, 1971). These latter methods have usually consisted of one of two types, involving either sleep EEG recordings or direct measures of the subjects’ motility by means of a recording apparatus attached to the bed. While there can be little doubt about the validity of using EEG for this purpose, problems of utility do arise because of equipmentexpense, complications of data reduction and so on. On the other hand, there does seem to be substantial evidence that direct measures of subjects’ motility are both valid and useful estimates of sleep disturbance. Perhaps the first such report is that by Laird & Drexel(1934),who used a ‘somnokinetograph’ to observe differential effects of ‘easy ’ and ‘hard to digest ’ meals on the quality of sleep innormal subjects. Schiele (1941) used a ‘motilograph’ in a study of the sleep of psychiatric patients and found that the motility measure was not only useful, but ‘greatly to be preferred ’ over less objective measures. Similarly, Cox & Marley (1959) and Hinton & Marley (1959) have reported on the use of a somewhat more elaborate electronic recording device, which was found to be useful in studying the effects of meprobamate and pentobarbitone sodium on sleep. Ulett et al. (1%2) also found measures of motility useful in evaluating the
effects of chlorprothixin and thioridazine, although Samuel (1964), in a study which differed in a number of details, found no effect of one of these drugs (thioridazine) on sleep motility. Nevertheless, Samuel, Cox & Marley and Hinton & Marley all found a significant correlation between motility measures and the nurse’s ratings of patient’s sleep disturbance - a finding which argues well for the validity of both motility measures and nurses’ ratings, even though this is clearly less than perfect. It would further appear that the use of questionnaires to identify subjects who complain of disturbed sleep is a genuinely effective method. Among the most recent examples, Monroe (1967) has reported a number of differences between ‘good’ and ‘poor’ sleepers differentiated on the basis of their responses to a 10-item sleep questionnaire. In addition, Johns et al. (1971) used a similar questionnaire to demonstrate significant differences in urinary free 11-OCHSin groups also labelled good and poor sleepers. These and other reports thus strongly argue that subjective, i.e. self-report, questionnaire data can be used to discriminate between different types of sleep groups, although the problem of response bias is always troublesome in the interpretation of subjective data. It thus seemed reasonable to the present authors that one could hypothesize a relationship between (a) motility measures and nurses’ ratings, on the one hand, and (b) questionnaire data, on the other. The questionnaire in this case was developed from the item pool of the Minnesota Multiphasic Personality Inventory (MMPI), * Department of Psychiatry, School of Medicine, Uni- because of its extremely broad use and because versity of Missouri - Columbia, Columbia, Missouri it could potentially be a relatively objective refinement over more subjective self-report 65201. t 915 Shorepoint Court, Alameda, California 94501. questionnaires. 4
MPS
48
50
DAVIDG . MCDONALD AND ELIZABETH A. KING METHOD
Subjects Subjects consisted of 19psychiatric in-patients at the University of Missouri Medical Center. The in-patient service is a small, intensive milieu treatment unit, and it was therefore possible to include nearly all patients admitted during the two-month period of data collection. There were eight females and 1 1 males, with an average age of 36.6 years and a range from 17 to 64 years. Since patients were selected without regard for diagnosis, there were relatively equal numbers with diagnoses falling in the categories of neurosis, psychosis, character disorder and chronic brain syndrome. Five patients showed a major symptom of depression, only one of which was psychotic. All patients were receiving some medication, although this consisted of a variety of drugs with no one drug predominating.
gue, disturbing dreams, and the like. These items were combined to form a ‘Complains of Sleep Disturbance’ or CSD scale. The CSD scale consists of 20 items, which, with the direction of scoring indicated, are the following: 3(F), 5(T), 31(T), 43(T), 152(F), 163(F), 189(T), 21 1(T), 241(T), 320(T), 329(F), 340(T), 388(T), 425(T), 442(T), 466(F),480(T), 505(T), 545(T), 559(T). No more than five of these items overlap with any of the existing standardized MMPI scales, and the average overlap is 1-75 items per scale. All MMPI scores were readily available, since this test was routinely administered to all patients on admission.
RESULTS Since in the present study the patient sample and many of the details of the data collection procedures differed from those of previous reports, it was deemed necessary first to reObjective measures of sleep disturbance establish their finding of a correlation between Sleep motility was recorded by means of a,simple, tamper-proof stabilimeter, which consisted of a metal sleep motility scores and sleep ratings. The biarm attached to the patient’s bed which, in turn, was serial correlation between these two measures in good agreemechanically connected to the pen of a kymograph was found to be 0.58 ( P < recording apparatus. Recordings were made of an ment with the previous reports. Next, rank-order correlation coefficientswere entire night of sleep, after which the number of movements was totalled and converted into a motility score computed between the MMPI scales, including in terms of movements per hour, in order to equate for the CSD score, and the motility measures. Only the fact that the total time in bed varied between the correlation between the CSD score and motipatients and nights. Stabilimeters were attached toeach lity was significant ( r = 0.62; P < 0.02); the next patient’s bed for a minimum of two nights, and the highest correlation with motility was considermotility scores of the several nights were averaged to ably lower ( r = 0.35) and not significant. Subprovide a single score for each patient. jects were then divided into high and lower CSD The second measure of sleep disturbance, using ratings, was obtained in the followingmanner: one of us score groups, by dividing at the median CSD (E. K.) abstracted from each patient’s chart all state- score, and a one-tailed Mann-Whitney U test ments which referred to sleep, whether in the nursing was computed between their motility scores. notes or medical history. This gave a listing of each Results of this test were significant at the 0.025 patient’s sleep history, but did not reveal the diag- level of confidence ( U = 17), indicating signifinosis, presence or absence of critical symptoms such as cantly higher motility scores in the high CSD depression, or any other obviouslycontaminatinginfor- score group; the mean motility scores for the mation. The other experimenter (D. M.), who also did high and low CSD groups were 6.08 and 3.31 not know the patients’ motility scores, was then able movements per hour, respectively, with standard blindly to assign a rating of 1 or 2, representing ‘ no or deviations of 3.02 and 1.58. mild sleep disturbance ’ and ‘greater than average Repeating these analyses with sleep ratings sleep disturbance ’,respectively. Parenthically, it might instead of motility scores, biserial correlations be added that the nursing notes provided what was were computed between the ratings and the clearly the greatest single influence on these ratings. MMPI scales, including the CSD scale. Again, Questionnaire measure of sleep disturbance only the correlation between the sleep rating and The questionnaire data consisted of all items from the CSDscale was significant( r = 0.57; P < OsOl), the MMPI which refer to problems in sleeping, fati- the remainder of the correlations being substanO a O I ) ,
Measures of sleep disturbance
51
Table 1. Comparison of low CSD v. high CSD groups on age and MMPI scores (not K-corrected). (The P values are one-tailed.) Low CSD High CSD Comparison Variable CSD scores Age MMPI scales L F K
Hs D HY Pd Mf - males Mf - females Pa
Pt sc Ma Si
-
7
T
Mean
S.D.
Mean
S.D.
5.00 38.44
2.9 1 12.08
10.80 35.00
2.09 14.40
7.00 3 -77 18-00 10.33 29.89 30.22 18-22 25.40 39.25 12.78 18.78 16.33 16.00 37.78
3.23 2.74
4.50 8.90 10.70 14-00 34.00 3 1 *70 23-90 27.83 34-50
2.01 3.56 2.90 4.20 7.1 1 5.27 5.63 4.67 2-67 2.88 5.92 7.18 4-08 9-02
5.60
7-60 8.62 8.11 6-09 5.24 3.49 3 -68 13-97 13.98 3-43 12*%
15.10
29-90 28.30 16.40 41.30
1-89 3-34 3-31 1.21 1 -06
0.44 1 -99 0.73 1-87 1 44 2.11 2.18 0.22 0.67
< 0.05 < 0.0025 < 0.0025 -
-
< 0.05
< 0-05
-
< 0.025 < 0.025
-
tially lower and not significant. A Mann-Whit- who showed evidence of depression in both the ney U test was then computedtxtween the CSD high and low CSD groups. scores of those given sleep ratings of 1 v. 2; the U was 21.5 (one-tailed P < 0.06). DISCUSSION Lastly, a number of additional comparisons were made between the two groups created by Several findings emerge from the present dividing at the median CSD score. There were study. First, a significant correlation was obnine subjects in the low CSD group (five male, served between motility scores and sleep ratings. four female) and 10 subjects in the high CSD This occurred even though there were many group (six male, four female). The results are differences in subjects, equipment and techsummarized in Table 1. It can be seen that, while niques between this and the studies reported the groups did not differ significantly in age, there by Cox & Marley (1959), Hinton & Marley (1959) were significant differences in several of the and Samuel (1964). Secondly, it was demonstrated that a sleep MMPI scales, specifically,the L, F, K, Pd, Rand Sc scales. In the case of the Mf scale, the questionnaire, i.e. the CSD scale, could be used comparison between females was significant at to differentiate both those with high v. low motithe 0.05 level, while that for the males was not lity scores, as well as those with high v. low sleep significant. There were no differences between ratings. In addition, both motility scores and males and females on any of the other MMPI sleep ratings were significantly correlated with CSD scores, but not with scores on any of the scales. Finally, there were too few subjects in any major MMPI scales. As indicated in the introducsingle diagnostic or treatment category to estab- tion, this was a major hypothesis of the present lish relationships with the present results. There study. Previous reports in the literature not only were approximately equal numbers of patients made this a reasonable prediction, but it also 4-2
52
DAVIDG. MCDONALD AND ELIZABETH A. KING
supports Monroe’s finding (1%7) of differences in body movements of good v. poor sleep groups. There are, however, several important differences. Monroe used a polygraph to record body movements, along with a number of other variables; the stabilimeters used by the present authors were simple spring-wound mechanisms, which have an advantage of requiring attention only once at night and again in the morning. This is not only more convenient, but also reduces the effects of an extraneous variable, the knowledge that ‘I am serving in an experiment’, on the subjects. In addition, Monroe used an explicit sleep questionnaire to identify good and poor sleep subjects. The CSD scale, on the other hand, has the major advantage that it is subtle in the sense that the 20 items are embedded in the 566 item MMPI. One can only speculate, in all studies using such explicit questionnaires, on the extent of response bias or self-fulfilling prophecy in the findings. That is, an individual who has just specifically reported that he is a poor sleeper could well feel compelled to sleep more poorly when being observed by the experimenter. While the present data strongly suggest that this might not be an overwhelming factor, the question does remain largely unanswered. On the other hand, the authors do hasten to add the cautionary note that the CSD scale has yet to be used with normal subjects, such as those in the studies of Monroe or Johns et al. (1971). The last finding in the present study was the significant difference between low and high CSD groups on a number of the additional MMPI scales. Both Monroe (1%7) and Johns et al. (197 1) made similar comparisons between their good and poor sleep groups of male subjects drawn from normal (i.e. non-patient) populations. The present results would appear to be more similar to Monroe’s, which might well have
been predicted on the basis of the fact that he used subjects who responded to an advertisement, whereas Johns et al. limited themselves to fourth-year medical students. Nevertheless, the present results certainly support Monroe’s conclusion that poorer sleepers show more evidence of psychological disturbance; further, even in a group of psychiatric patients which is generally disturbed, the poorest sleepers are still the most disturbed. The fact that the depressed patients in the present sample were equally divided into the high and low CSD groups may not be significant in such small groups. Indeed, there are reports, such as that by Naylor & LePoidevin (1972). which provide valuable and extensive information on the relationships between sleep disturbance and depression.
SUMMARY Several measures of sleep disturbance were collected from a heterogeneous group of 19 psychiatric adult in-patients. These measures consisted of ( I ) sleep motility, by means of a device connected to the patient’s bed, (2) a rating of sleep disturbance, based primarily on references to sleeping difficulties mentioned in the nursing notes, and (3) the score on the ‘Complainsof Sleep Disturbance ’ or CSD scale,based on all items in the MMPI which refer to difficulties in sleep, disturbing dreams, etc. There was a significant correlation between measures of sleep motility and sleep ratings. The CSD scores significantly differentiated those with high v. low motility scores, as well as those with high v. low sleep ratings. Both of these scores were significantly correlated with CSD scores but not with other MMPI scales. Low and high CSD groups differed significantly on several MMPI scales (L, F, K, Pd, Pt and Sc; Mf in female subjects only), supporting the conclusion of greater disturbance in poorer sleepers, even in a generally disturbed group of psychiatric patients.
Measures of sleep disturbance
53
REFERENCES COX,G. H. & MARLEY,E. (1959). The estimation of motility during rest or sleep. J. Neurol. Neurosurg. Psychiat. 22, 5740. HINTON,J. M. & MARLEY, E. (1959). The effects of meprobamate and pentobarbitone sodium on sleep and motility during sleep: a controlled trial with psychiatric patients. J. Neurol. Neurosurg. Psychiat. 22, 137-140. JOHNS,M. W. (1971). Methods for assessing human sleep. Archs int. Med. 127, 484-492. JOHNS,M. W., GAY,T. J. A., MASTERTON, J. P. & BRUCE,D. W. (1971). Relationship between sleep habits, adrenocortical activity and personality. Psychosom. Med. 33,499-508. H. (1934). Effects of varying LAIRD,D. A. & DREXEL, types of food in offsetting sleep disturbances caused by hunger pangs and gastric distress: children and adults. J. Am. diet. Ass. 10, 89-99.
MONROE,L. J. (1%7). Psychological and physiological differences between good and poor sleepers. J. abnorm. Psychol. 72, 255-264. NAYLOR,G. J. & LEPOIDEVIN, D. (1972). Sleep patterns in depressive states. Br. J. med. Psychol. 45, 171-1 76. SAMUEL, J. G. (1964). Sleep disturbance in depressed patients: objective and subjective measures. Br. J. Psychiat. 110,711-719. SCHIELE, B. C. (1941). A clinical study of sleep disturbances. Am. J. Psychiat. 98, 119-123. ULETT,G. A., HEUSLER, A. F., WORD,V. I. &WORD, T. J. (1962). Mechanical and electronic techniques in the measurement of psychopharmacologic response. In J. H. Nodine & J. H. Moyer (eds.), The First Hahnemann Symposium on Psychosomatic Medicine. Philadelphia: Lea & Febiger.
49
Measures of sleep disturbance in psychiatric patients BY DAVID G. McDONALD* AND ELIZABETH A. KING? Attempts to measure sleep disturbance have appeared in the literature for quite some time, the first report to the authors’ knowledge dating back 40 years. Measurements in these reports have included subjective reports from subjects, often by means of a questionnaire, as well as more objective methods (Johns, 1971). These latter methods have usually consisted of one of two types, involving either sleep EEG recordings or direct measures of the subjects’ motility by means of a recording apparatus attached to the bed. While there can be little doubt about the validity of using EEG for this purpose, problems of utility do arise because of equipmentexpense, complications of data reduction and so on. On the other hand, there does seem to be substantial evidence that direct measures of subjects’ motility are both valid and useful estimates of sleep disturbance. Perhaps the first such report is that by Laird & Drexel(1934),who used a ‘somnokinetograph’ to observe differential effects of ‘easy ’ and ‘hard to digest ’ meals on the quality of sleep innormal subjects. Schiele (1941) used a ‘motilograph’ in a study of the sleep of psychiatric patients and found that the motility measure was not only useful, but ‘greatly to be preferred ’ over less objective measures. Similarly, Cox & Marley (1959) and Hinton & Marley (1959) have reported on the use of a somewhat more elaborate electronic recording device, which was found to be useful in studying the effects of meprobamate and pentobarbitone sodium on sleep. Ulett et al. (1%2) also found measures of motility useful in evaluating the
effects of chlorprothixin and thioridazine, although Samuel (1964), in a study which differed in a number of details, found no effect of one of these drugs (thioridazine) on sleep motility. Nevertheless, Samuel, Cox & Marley and Hinton & Marley all found a significant correlation between motility measures and the nurse’s ratings of patient’s sleep disturbance - a finding which argues well for the validity of both motility measures and nurses’ ratings, even though this is clearly less than perfect. It would further appear that the use of questionnaires to identify subjects who complain of disturbed sleep is a genuinely effective method. Among the most recent examples, Monroe (1967) has reported a number of differences between ‘good’ and ‘poor’ sleepers differentiated on the basis of their responses to a 10-item sleep questionnaire. In addition, Johns et al. (1971) used a similar questionnaire to demonstrate significant differences in urinary free 11-OCHSin groups also labelled good and poor sleepers. These and other reports thus strongly argue that subjective, i.e. self-report, questionnaire data can be used to discriminate between different types of sleep groups, although the problem of response bias is always troublesome in the interpretation of subjective data. It thus seemed reasonable to the present authors that one could hypothesize a relationship between (a) motility measures and nurses’ ratings, on the one hand, and (b) questionnaire data, on the other. The questionnaire in this case was developed from the item pool of the Minnesota Multiphasic Personality Inventory (MMPI), * Department of Psychiatry, School of Medicine, Uni- because of its extremely broad use and because versity of Missouri - Columbia, Columbia, Missouri it could potentially be a relatively objective refinement over more subjective self-report 65201. t 915 Shorepoint Court, Alameda, California 94501. questionnaires. 4
MPS
48
50
DAVIDG . MCDONALD AND ELIZABETH A. KING METHOD
Subjects Subjects consisted of 19psychiatric in-patients at the University of Missouri Medical Center. The in-patient service is a small, intensive milieu treatment unit, and it was therefore possible to include nearly all patients admitted during the two-month period of data collection. There were eight females and 1 1 males, with an average age of 36.6 years and a range from 17 to 64 years. Since patients were selected without regard for diagnosis, there were relatively equal numbers with diagnoses falling in the categories of neurosis, psychosis, character disorder and chronic brain syndrome. Five patients showed a major symptom of depression, only one of which was psychotic. All patients were receiving some medication, although this consisted of a variety of drugs with no one drug predominating.
gue, disturbing dreams, and the like. These items were combined to form a ‘Complains of Sleep Disturbance’ or CSD scale. The CSD scale consists of 20 items, which, with the direction of scoring indicated, are the following: 3(F), 5(T), 31(T), 43(T), 152(F), 163(F), 189(T), 21 1(T), 241(T), 320(T), 329(F), 340(T), 388(T), 425(T), 442(T), 466(F),480(T), 505(T), 545(T), 559(T). No more than five of these items overlap with any of the existing standardized MMPI scales, and the average overlap is 1-75 items per scale. All MMPI scores were readily available, since this test was routinely administered to all patients on admission.
RESULTS Since in the present study the patient sample and many of the details of the data collection procedures differed from those of previous reports, it was deemed necessary first to reObjective measures of sleep disturbance establish their finding of a correlation between Sleep motility was recorded by means of a,simple, tamper-proof stabilimeter, which consisted of a metal sleep motility scores and sleep ratings. The biarm attached to the patient’s bed which, in turn, was serial correlation between these two measures in good agreemechanically connected to the pen of a kymograph was found to be 0.58 ( P < recording apparatus. Recordings were made of an ment with the previous reports. Next, rank-order correlation coefficientswere entire night of sleep, after which the number of movements was totalled and converted into a motility score computed between the MMPI scales, including in terms of movements per hour, in order to equate for the CSD score, and the motility measures. Only the fact that the total time in bed varied between the correlation between the CSD score and motipatients and nights. Stabilimeters were attached toeach lity was significant ( r = 0.62; P < 0.02); the next patient’s bed for a minimum of two nights, and the highest correlation with motility was considermotility scores of the several nights were averaged to ably lower ( r = 0.35) and not significant. Subprovide a single score for each patient. jects were then divided into high and lower CSD The second measure of sleep disturbance, using ratings, was obtained in the followingmanner: one of us score groups, by dividing at the median CSD (E. K.) abstracted from each patient’s chart all state- score, and a one-tailed Mann-Whitney U test ments which referred to sleep, whether in the nursing was computed between their motility scores. notes or medical history. This gave a listing of each Results of this test were significant at the 0.025 patient’s sleep history, but did not reveal the diag- level of confidence ( U = 17), indicating signifinosis, presence or absence of critical symptoms such as cantly higher motility scores in the high CSD depression, or any other obviouslycontaminatinginfor- score group; the mean motility scores for the mation. The other experimenter (D. M.), who also did high and low CSD groups were 6.08 and 3.31 not know the patients’ motility scores, was then able movements per hour, respectively, with standard blindly to assign a rating of 1 or 2, representing ‘ no or deviations of 3.02 and 1.58. mild sleep disturbance ’ and ‘greater than average Repeating these analyses with sleep ratings sleep disturbance ’,respectively. Parenthically, it might instead of motility scores, biserial correlations be added that the nursing notes provided what was were computed between the ratings and the clearly the greatest single influence on these ratings. MMPI scales, including the CSD scale. Again, Questionnaire measure of sleep disturbance only the correlation between the sleep rating and The questionnaire data consisted of all items from the CSDscale was significant( r = 0.57; P < OsOl), the MMPI which refer to problems in sleeping, fati- the remainder of the correlations being substanO a O I ) ,
Measures of sleep disturbance
51
Table 1. Comparison of low CSD v. high CSD groups on age and MMPI scores (not K-corrected). (The P values are one-tailed.) Low CSD High CSD Comparison Variable CSD scores Age MMPI scales L F K
Hs D HY Pd Mf - males Mf - females Pa
Pt sc Ma Si
-
7
T
Mean
S.D.
Mean
S.D.
5.00 38.44
2.9 1 12.08
10.80 35.00
2.09 14.40
7.00 3 -77 18-00 10.33 29.89 30.22 18-22 25.40 39.25 12.78 18.78 16.33 16.00 37.78
3.23 2.74
4.50 8.90 10.70 14-00 34.00 3 1 *70 23-90 27.83 34-50
2.01 3.56 2.90 4.20 7.1 1 5.27 5.63 4.67 2-67 2.88 5.92 7.18 4-08 9-02
5.60
7-60 8.62 8.11 6-09 5.24 3.49 3 -68 13-97 13.98 3-43 12*%
15.10
29-90 28.30 16.40 41.30
1-89 3-34 3-31 1.21 1 -06
0.44 1 -99 0.73 1-87 1 44 2.11 2.18 0.22 0.67
< 0.05 < 0.0025 < 0.0025 -
-
< 0.05
< 0-05
-
< 0.025 < 0.025
-
tially lower and not significant. A Mann-Whit- who showed evidence of depression in both the ney U test was then computedtxtween the CSD high and low CSD groups. scores of those given sleep ratings of 1 v. 2; the U was 21.5 (one-tailed P < 0.06). DISCUSSION Lastly, a number of additional comparisons were made between the two groups created by Several findings emerge from the present dividing at the median CSD score. There were study. First, a significant correlation was obnine subjects in the low CSD group (five male, served between motility scores and sleep ratings. four female) and 10 subjects in the high CSD This occurred even though there were many group (six male, four female). The results are differences in subjects, equipment and techsummarized in Table 1. It can be seen that, while niques between this and the studies reported the groups did not differ significantly in age, there by Cox & Marley (1959), Hinton & Marley (1959) were significant differences in several of the and Samuel (1964). Secondly, it was demonstrated that a sleep MMPI scales, specifically,the L, F, K, Pd, Rand Sc scales. In the case of the Mf scale, the questionnaire, i.e. the CSD scale, could be used comparison between females was significant at to differentiate both those with high v. low motithe 0.05 level, while that for the males was not lity scores, as well as those with high v. low sleep significant. There were no differences between ratings. In addition, both motility scores and males and females on any of the other MMPI sleep ratings were significantly correlated with CSD scores, but not with scores on any of the scales. Finally, there were too few subjects in any major MMPI scales. As indicated in the introducsingle diagnostic or treatment category to estab- tion, this was a major hypothesis of the present lish relationships with the present results. There study. Previous reports in the literature not only were approximately equal numbers of patients made this a reasonable prediction, but it also 4-2
52
DAVIDG. MCDONALD AND ELIZABETH A. KING
supports Monroe’s finding (1%7) of differences in body movements of good v. poor sleep groups. There are, however, several important differences. Monroe used a polygraph to record body movements, along with a number of other variables; the stabilimeters used by the present authors were simple spring-wound mechanisms, which have an advantage of requiring attention only once at night and again in the morning. This is not only more convenient, but also reduces the effects of an extraneous variable, the knowledge that ‘I am serving in an experiment’, on the subjects. In addition, Monroe used an explicit sleep questionnaire to identify good and poor sleep subjects. The CSD scale, on the other hand, has the major advantage that it is subtle in the sense that the 20 items are embedded in the 566 item MMPI. One can only speculate, in all studies using such explicit questionnaires, on the extent of response bias or self-fulfilling prophecy in the findings. That is, an individual who has just specifically reported that he is a poor sleeper could well feel compelled to sleep more poorly when being observed by the experimenter. While the present data strongly suggest that this might not be an overwhelming factor, the question does remain largely unanswered. On the other hand, the authors do hasten to add the cautionary note that the CSD scale has yet to be used with normal subjects, such as those in the studies of Monroe or Johns et al. (1971). The last finding in the present study was the significant difference between low and high CSD groups on a number of the additional MMPI scales. Both Monroe (1%7) and Johns et al. (197 1) made similar comparisons between their good and poor sleep groups of male subjects drawn from normal (i.e. non-patient) populations. The present results would appear to be more similar to Monroe’s, which might well have
been predicted on the basis of the fact that he used subjects who responded to an advertisement, whereas Johns et al. limited themselves to fourth-year medical students. Nevertheless, the present results certainly support Monroe’s conclusion that poorer sleepers show more evidence of psychological disturbance; further, even in a group of psychiatric patients which is generally disturbed, the poorest sleepers are still the most disturbed. The fact that the depressed patients in the present sample were equally divided into the high and low CSD groups may not be significant in such small groups. Indeed, there are reports, such as that by Naylor & LePoidevin (1972). which provide valuable and extensive information on the relationships between sleep disturbance and depression.
SUMMARY Several measures of sleep disturbance were collected from a heterogeneous group of 19 psychiatric adult in-patients. These measures consisted of ( I ) sleep motility, by means of a device connected to the patient’s bed, (2) a rating of sleep disturbance, based primarily on references to sleeping difficulties mentioned in the nursing notes, and (3) the score on the ‘Complainsof Sleep Disturbance ’ or CSD scale,based on all items in the MMPI which refer to difficulties in sleep, disturbing dreams, etc. There was a significant correlation between measures of sleep motility and sleep ratings. The CSD scores significantly differentiated those with high v. low motility scores, as well as those with high v. low sleep ratings. Both of these scores were significantly correlated with CSD scores but not with other MMPI scales. Low and high CSD groups differed significantly on several MMPI scales (L, F, K, Pd, Pt and Sc; Mf in female subjects only), supporting the conclusion of greater disturbance in poorer sleepers, even in a generally disturbed group of psychiatric patients.
Measures of sleep disturbance
53
REFERENCES COX,G. H. & MARLEY,E. (1959). The estimation of motility during rest or sleep. J. Neurol. Neurosurg. Psychiat. 22, 5740. HINTON,J. M. & MARLEY, E. (1959). The effects of meprobamate and pentobarbitone sodium on sleep and motility during sleep: a controlled trial with psychiatric patients. J. Neurol. Neurosurg. Psychiat. 22, 137-140. JOHNS,M. W. (1971). Methods for assessing human sleep. Archs int. Med. 127, 484-492. JOHNS,M. W., GAY,T. J. A., MASTERTON, J. P. & BRUCE,D. W. (1971). Relationship between sleep habits, adrenocortical activity and personality. Psychosom. Med. 33,499-508. H. (1934). Effects of varying LAIRD,D. A. & DREXEL, types of food in offsetting sleep disturbances caused by hunger pangs and gastric distress: children and adults. J. Am. diet. Ass. 10, 89-99.
MONROE,L. J. (1%7). Psychological and physiological differences between good and poor sleepers. J. abnorm. Psychol. 72, 255-264. NAYLOR,G. J. & LEPOIDEVIN, D. (1972). Sleep patterns in depressive states. Br. J. med. Psychol. 45, 171-1 76. SAMUEL, J. G. (1964). Sleep disturbance in depressed patients: objective and subjective measures. Br. J. Psychiat. 110,711-719. SCHIELE, B. C. (1941). A clinical study of sleep disturbances. Am. J. Psychiat. 98, 119-123. ULETT,G. A., HEUSLER, A. F., WORD,V. I. &WORD, T. J. (1962). Mechanical and electronic techniques in the measurement of psychopharmacologic response. In J. H. Nodine & J. H. Moyer (eds.), The First Hahnemann Symposium on Psychosomatic Medicine. Philadelphia: Lea & Febiger.
