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The diurnal variation of plasma cortisol levels in depression
J Psychosomatic Res
,1966,Vol
10, PP
189 to 195
Pergamon Press Lfd
Prrnted m Northern Ireland
THE DIURNAL VARIATION OF PLASMA LEVELS IN DEPRESSION*
CORTISOL
D. J. MCCLURE (Recemed 25 February 1966) DEPRESSIVE rllnesses are suitable for the study of adrenocortrcal acttvrty m relatron to emotion because they are common and the patrents are usually manageable without medrcatton for long enough to permtt chmcal observatrons and the collectron of laboratory data The findings of Board et al. [ 1,2] showed elevation of the 17-hydroxycorticosterord levels in the plasma of the more severe depressions, higher cortrsol values being found in the retarded depressrons than m the agitated depresstons. Gibbons and McHugh [3] reported a posrttve correlation between the severity of the depressive illness and the height of the plasma corttsol levels The existence of a circadian rhythm m the secretion of adrenal steroids has been estabhshed [4, 51. The cycle of the 17-hydroxycorttcosterord levels over a 24-hour period m normal subjects and under ordinary condtttons shows that the lowest concentratron of these steroids IS found between 10 00 pm. and 2.00 a m., from 2.00 a m. until 4 00 a m. there IS a gradual elevation, which IS then followed by a steeper rtse reaching maximum values m the region of 6.00 a m. to 8 00 a.m. After thus, there IS a sharp declme until noon and then a more gradual fall until 10 00 p.m. when the cycle starts anew. It was decided: (1) To measure the diurnal varratron m the levels of plasma cortrsol in psychiatric patients suffering from a psychotic depressive illness. (2) To determine whether these levels formed a characteristrc pattern for the psychotrc depressive group as a whole or whether there was an mdtvtdual pattern for each patient To consider posstble etrologrcal factors m the dtsturbed sleep rhythm which (3) occurs m the depressive psychoses.
MATERIAL The mvestlpatlon was carried out on seven psychlatrlc patients, two male and five female, with a mean age of 60 years and seven normal controls of comparable age and sex The activity of the . . . _. . adrenal cortex, with regard to the secretion ofcortlsol, IS llttle at&ted by the aging process in healthy persons of either sex [6, 71. Each patient was diagnosed as suffermg from a depressive psychosls [8,9]. The primary symptoms for the diagnosis were’ a mood of depresslon, a dmrnal mood change with exacerbation m the mormng, msomma with early mornmg awakening, and dlmmutlon of interest m the social environment Other symptomatic features were usually present mcludmg fatigue, selfblame, death wishes, loss of appetite, weight and libido, and disturbance m motor activity, either retardation or agltatlon. The diagnosis was made independently by two psychlatnsts, one of whom was the author. Added confirmatory data were supplied by the depressive scale of the Mmnesota Multi-Phaslc Personality Inventory (MMPI) and the Rorschach test, completed by a member of the psychology staff. All SubJects were considered sultable for electro-convulsive treatment The patients were receivmg no medlcatlon at the time of admlsslon to the study and had been free from all drugs for a rmmmum period of 4 weeks prior to It The difficulty m obtammg such cases IS obvious because most patients * From the Allan Memorial Institute of Psychiatry, McGill Umverslty, Montreal. 189
190
D. J. MCCLURE
are placed on medlcatton m-mediately after being seen by then own physician or by the psychtatrrst who carries out the mttlal Interview m order to tide the patient over untd he 1s admitted to hospital. This accounts for the small number of cases m the study Each candidate suitable for the mvesttgatron was placed on placebo three times dally and once at night for 48 hr During this time, blood was drawn over two consecutive 24-hour periods at intervals which would give most mformatton about the diurnal adrenocorttcal acttvrty, namely, 7 00 a m., 12 noon and 10 00 p.m METHODS Fifteen mllhhtres of venous blood were drawn at 6 45 a m , 11 45 a.m and 10 00 p m on two consecutive days into 20 ml test tubes containing hepann, then centrifuged and the plasma separated and frozen untd assayed The plasma cortlsol levels were determined by a slight modtfication of the dialysis method described by Murphy et al. [lo] This method measures both cortlsol and corttcosterone m the plasma, but since the amount of corttscosterone IS only about 1/13th that of cortnol, the results obtained here will be referred to as plasma cortlsol [ll]. The statistical analysts used m this experiment was that described by Wmer [12] for a two-factor expenment with repeated measures. In carrying through this analysis on the raw data, it was found that the parts pooled to form the denommators of the F-ratio lacked homogeneity due to the high values obtained from the patients at 7 00 a m. Therefore, the analysts was conducted on the logarithm to base 10 of the data and this time the parts pooled to form the denommators of the F-ratios were homogeneous. t-tests were conducted on those sources of variation that proved to be srgmficant. RESULTS The data for the mvesttgation on seven depressed patients and the seven normal sublects are shown on Table 1. The analysis of vartance table for this data IS given m Table 2. Examination of these results shows that there was a very highly slgmficant difference between the two groups of subjects (P c 0 0005, Table 2) The mean and standard error of all twenty-one values for the seven subJects was 27 8 f 2 7 ,ug/lOO ml plasma, whrle the corresponding values for the normal was 11 8 i 1 3 pg/lOO ml plasma (Table 3) There was also a very highly slgmficant dtfference due to diurnal vartatlon m the values (P < 0 0005, Table 2). Subsequent I-tests showed that there were stgmficant differences between the 7.00 a m and noon values (0 02 > P > 0 01, Table 3) and also between the noon and 10 00 p m values (0 01 > P > 0 001) It will be noted that the differences between the two groups was greater at 7 00 a m than at noon or at 10.00 p m. (Table 3). TABLE I.-PLASMA
Pattents
Normals
CORTISOL LEVELS (pg/lOO ml) IN NORMAL
Age
(yd
SUBJECTS AND IN DEPRESSED PATIENTS
Sex
1 2 3 4 5 6 7
F F M M F F F
48 62 70 71 56 64 48
29 00 34 00 31 00 34 00 53 00 61 00 34 00
20 50 1875 1925 1600 32 75 37 25 29 00
1875 1550 1250 1175 31 25 23 50 21 50
1 2 3 4 5 6 7
F M F F M F F
60 66 49 65 73 53 54
23 00 1700 16 50 22 50 17 50 15 50 1150
1400 13 50 13 50 16 50 900 11 25 8 00
500 2 75 3 25 600 6 00 9 50 5 00
700am
12 noon
10OOpm.
Sublect
The differences between the mean of values obtamed from samples taken at 7 00 a m and noon (9 9) was greater than those obtamed between noon and 10 00 p rn* (6 2) (Table 3) However. exammatton of the data m Table 4 shows that differences between the logarithm of the values at 10 bo p m and noon are bigger than those between 7 00 p m and noon. Thtsmteractton is apparently not statistically slgmficant if one apphes the conservative test, as descrtbed m the next paragraph The discrepancy between the values obtained m Tables 3 and 4 is due to the conversion of the raw values mto logartthms which reduced the larger numbers to a greater extent than it dtd the smaller ones. A graph of the raw values 1s shown m Fig 1 It IS obvious m this figure that dlfferences between patrents and normals were greater at 7 00 a m than at noon or 10 00 p m
The dmrnal variatton of plasma corttsol levels in depression TABLE 2.-ANALYSIS
OF VARIANCE TABLE FOR TWO-FACTOR
191
EXPERIMENT WITH REPEATED MEASURES
Sum of squares
Degrees of freedom
Variance estimate
Between SubJcCts A (Effect of depression) Subjects wmun groups
2 13080280 1 70323989 0 42756291
13 1 12
1 703239s9* 0 03563024
Wrthm SubJects B (Diurnal vartatron) AB B x subjects wtthm groups
1 69179551 1 30524173 0 14450158 0 24205220
28 2 2 24
065262087* 007225079t 0 01008551
Source
* Stgmficant at the 0 05 ‘A level t Srgmficant at the 2 5 % level.
TABLE ~-SUMMARY
Subjects
OF DEPRESSION x DIURNAL VARIATION INTERACTION
7OOam*
Patients Normals Mean:
12 noon
39 4 17 6 28 5
1000pm
Meant
19 3 54 124
27 8 11 8
24~8 123 186
Standard error f27 *13
* The mean value shown for a given time IS the mean of seven determmatrons. t The values shown m this column are the mean of twenty-one estrmatrons. $ The values shown m this row are the mean of fourteen esttmatlons
TABLE 4 -SUMMARY
Subjects
OF THE LOG VALUES OF DEPRESSION x DIURNAL VARIATION INTERACTION 12noon
700am.
1000pm
Total
Patients Normals
110579 8 6558
9 6219 75326
8.8287 48622
295085 210506
Total
197137
171545
13 6909
505591
45 t-
2 8
(‘\ \
q 35-
Patients
1, \
s P 25L $
__--_--
Normals
\
\
\
\
\ '.B---------__-_--_--__~
57om
I
lZ"oo"
FIG 1 Diurnal variatton in the plasma corttsol concentrations subjects. 4
1
IOwn
of normal and depressed
192
D. J. MCCLURE
The mteractton between the effect of depression and the diurnal variation was stattstmally slgmficant (0 025 > P > 0 01, Table 2) This level of stgmficance was reached when one used the dmrnal variation X SubJects withm groups error which in this analysis is less than the SubJects within groups error In short, the ordinary test led to a statlsttcally sigmficant result for the mteractlon but when repeated with the subjects wtthm groups error which was larger, the results do not quite achteve sigmficance (0 20 > P > 0 10, Table 2). DISCUSSION
The levels of plasma cortisol were very much higher in the psychotrcally depressed patrents than m the normal subjects. However, there were at least three factors m addition to the prrmary mood disturbance contrrbutmg to these initrally high values. They Included the stresses produced (a) by being admitted to hospital [ 13, 141; (b) by undergoing the procedure of vempuncture and (c) the absence of any sedative medrcatron which would lower the hormone values [16, 171 The role played by these factors IS probably only a mmor one but they should be taken mto consrderatron when evaluatmg the differences between the normal subjects and the depressed patients. Board et al [2] hmitmg their investigatron to exammmg morning samples of blood, showed that raised levels of adrenocortical hormone occurred in depressed patients at thus time of day. The present results indicate that the hrgh cortrsol levels found m depressive illness extend throughout the 24-hour period with the highest A good correlatron was found between the values occurrmg m the early morning. severity of the depression and hormone levels m the plasma (Table 5), which IS m agreement with the work of Gibbons and McHugh [3]. The two cases (Numbers 6 and 5) with marked subjective and motor retardation had higher levels than the others, all of whom were agitated. This supports the findings of Board et al. [2]. TABLE
~--PLASMA
Clinical rating
++++ +++ +-I+ 0
CORTISOL LEVELS @g/l00 ml) ACCORDING CLINICAL RATING
Number of estimations 21 6 9 6 9
TO
Mean and standard error 27 8 200 13 9 155 105
+ f * k $-
2 7 ,ng/lOO ml 142~g/lOOmI 7 1 ,ug/lOO ml 106,@00ml 53,ug/lOOml
No specrfic dmrnal plasma cortrsol curve pathognomomc of psychotic depressive illness was found. The cortisol levels varied at different times of the day m all patrents m a similar fashion to that found in normal subjects wrth the highest level present m the morning, the next highest at noon, and the lowest m the evenmg. This suggests that m depressed patients, the same central mechanism which controls the normal diurnal rhythm of cortrsol secretion is stall operating, but that It IS greatly accelerated, causing a srgmficant increase in the adrenocortrcal actrvlty whrch m turn produces the hrgh perrpheral blood hydrocortrsone levels. The work of Grbbons [18], usmg radroactive cortrsol to determine the adrenocortrcal secretion rate, confirmed this increase m adrenal activity m depressed subjects and rt demonstrated that there was a hrgh correlatron between the elevated plasma cortlsol levels and the cortrsol secretion rate Patients The sleep disturbance m psychotic depression has a characterlstrc pattern.
The diurnal vartatlon of plasma cortlsol levelsIn depresslon
193
usually state that they are able to get to sleep wlthout much difficulty but that they awaken m the early hours of the morning and cannot get back to sleep again. All seven depressed cases m the study had this typical disturbed sleep rhythm. A number of mvestlgators have put forward explanations for this sleep disturbance For example, Swift and Ehthorn [19] postulated that there was a primary hypothalamic disturbance which resulted m an mverslon of the sleep rhythm tending to produce increased wakefulness at night. Oswald et al. [20], after taking contmuous nocturnal encephalographic recordings, measurmg eye movements and bed movements, reported that they failed to reveal any characterlstlc abnormality of sleep m patients with melanchoha other than an excess of wakefulness. Another explanation might be that the primary disturbance m mood sets off a cham of events mvolvmg over-activity of certain hypothalamic functions, causing an increased output of ACTH which m turn produces over-activity of the adrenal cortex, leading to an elevation of the plasma cortlsol levels. Even though the markedly elevated morning values decline during the day, the 10 00 p m. evening levels, are still very high. In the diurnal cycle, the increase m the secretion of cortlsol commences about 2.00 a m. so that the already high plasma cortlsol levels are further increased during the early hours of the morning and this comcldes with the period of early morning awakening and increased wakefulness. There 1s a significant amount of evidence from animal experiments [21-231 and from clinical data [24-261 to support the view that cortlsol-like steroids m large quantities increase bram excitability. They also appear to interfere with the normal sleep rhythm. For example, Fox and Glfford [27] found increasing wakefulness to be one of the principal effects of ACTH and cortisone given to a variety of medical patients; and Levine [28] observed wakefulness in premature infants who were given dally injections ofACTH. The electroencephalographic findings [29] which reflect the neurophysiological changes produced by an excess of adrenal steroids, show a sigmficant amount of slow wave activity and increased sensitivity to hyperventilation. Whether the effects of these steroids on brain excltablhty are found under physlologlcal and pathological condltlons 1s still undetermined. Nevertheless, the evidence, according to Engel [30] 1s very suggestive that these hormones 1s excess do have a direct effect on brain function. It seems reasonable, therefore, to suggest that the very high plasma cortlsol levels found in psychotically depressed patients exert a stlmulatmg and excitatory action on the brain to produce the symptoms of early morning awakening or increased wakefulness found m this condition. SUMMARY The diurnal variation of plasma cortisol levels was studied in fourteen subjects, seven psychotically depressed patients and seven normal persons of comparable age and sex. The cortisol levels were higher in the patients and remained high throughout the 24 hr. The highest values occurred in the morning and the lowest at night. Good correlation was found between the severity of the clinical depression and the levels of plasma cortisol. Higher values were found in the retarded than in the agitated depressions. When the diurnal plasma cortisol values were plotted graphically, they did not form a pathognominic curve which would be of diagnostic use in psychotic depressive illnesses. Instead, each patient formed then own individual curve. The central
194
D. J. MCCLURE
mechanism controlling the normal diurnal rhythm of cortisol secretlon appeared to be still operating but greatly accelerated. It IS hypothesized that cortisol 1s a good indxator of the severity of psychotic depression and that it may also be responsible for the early mornmg awakenmg which occurs m this illness. Acknowledgements-I particularly wish to thank Professor R A. Cleghorn, whose supervtston and gtudance were constant source of sttmulatton throughout thts work Dr. B Grad helped with the statist& data. The study was made possible by a Fellowshtp from the Medical Research Counctl of Canada.
REFERENCES 1. BOARD. F , PERSKY H. and HAMBURGD. A. Psychologtcal stress and endocrine function. Psychosom Med. 18, 324 (1956). 2. BOARDF , WADESONR and PERSKYH. Depressive affect and endocnne functtons A.M A. Archs Neural Psychzatry 78,612 (1957) 3. GIBBONSJ. L and MCHUGH P R Plasma cortlsol m depressive illness
J. Psychrat Res. 1, 162 (1963) 4. PINCUS G. A diurnal rythym m the excretion of urmary ketosterolds by young men. J. Clm. Endroc Metab 3, 195 (1943) 5. B~1s.sE. L , SANDBERGA A, NELSOND. H and EIK-NES K The normal levels of lFhydroxycortlscosterolds m the peripheral blood of man. J Chn. Invest 32, 818 (1953). 6. Pr~cus G Sterlod hormones and aam&?m man m AemP. Some Soczal and BzoloPlcal Asoects.
7. 8. 9. 10 11. 12.
ed. N. W. SHOCK. Pubhcatton No.065”of the Amerr~a~‘Assocratton for the Ad~ancem&t of Science, Washmgton, D C (1960) GRAD B , KRAL V. A , PAYNER C. and BERENSON J. Plasma and urinary corttcotds m young and old persons In preparation MAYER-GROSSW., SLATERE. and ROTH M Clmczal Psychzatry Cassell, London (1960). MURPHY H. B. M , WI~~KOWERE D. and CHANCEN. A. Crossculture mquny mto the symptomatology of depression Transcultl Psychlat Res 1, 5 (1964). MURPHYB. P., ENGELBERG W. and PAT~EEC J Simple method for the determmatton of plasma corttcotds J. Chn Endocr Metabol 23, 293 (1963). EIK-NES K , Methods for measurement ofcorttcosterotds m blood, m Hormones m Human Plasma, ed. H N ANTONIADES, p 358 Little, Brown, Boston, Mass (1960) Wmer B. J. Statrstlcal Prrncrples tn ExperImental Desrpn, chanter 7, Two-factor exoenment with 1
repeated measures. McGraw-Hnl, New York (1962).” A 13 MASON J W . SACHARE. J . FISHMANJ R . HAMBURGD A and HANDLONJ H. Cortlscosterold responses to hospttal adnussron. Archs. Gkn. Psychrat 13, 1 (1965) system, m Recent Progress m 14 MASON J W Psychological influences on pmntary-adrenalcortlcal Hormone Research. ed G PINCUS.vv. 345-389 Academic Press. New York (1959) 15 CLEGHORNR A , and GRAHAMB F.‘S’tudles of adrenal cortical ac&ty m psychdneurotlc subjects. Am J. Psychzat. 106, 668 (1950) 16. SHIBUSAWAK , SAITOS , FUKADA M , KAWAI T., YOMATOH and TOMIZAWAK Inhlbmon of the hypothalamus-neurohypophyseal neurosecretlon by chlorpromazme. Endocr Jap 2 (3), 189
(1955)
17 Co TUI F , BRIN~~ZERW , ORR A. and ORR E. L. Effect of chloropomazme and of reserpme on adrenocortlcal function Psychzat. Q. 34,47 (1960) 18 GIBBONSJ. L Corttsol secretion rate m depressive illness. Archs. Gen Psychzat 10, 572 (1964) of depression Proc 3rd 19. SWIM N and ELI~HORNA. An exnenmental annroach to the nroblem I Wld Conf Psychlat 2, 1372-1376 11962) _I 20 OSWALD I. BERGERR. J . JARAMILLOR A.. KEDDIEK M G . OLLEY P G and PLUNKE~~G B. Melanchoha and barbtturates A controlled EEG, body and’eye movement study of sleep Br. J Psychzat 109, 66 (1963). 21. W~~DBURY D M. Adrenal cortex and central nervous system Pharmac Rev 10, 276 (1958). 22. DE SALVA S J , HENDLEYC. D. and ERCOLI N Acute effects of ACTH and cortisone on brain excnablhty. Archs. Znt Pharmacodyn Ther 100, 35 (1954) 23 PINCUSJ B , NATELSONS and LUGOBOYJ. K Effect of epmephrme, ACTH and cortisone on citrate, calcmm. Proc Sot Exp Bzol Med 78, 24 (1951) 24 TORDA C and WOLFF H G Effects of various concentrations of adrenocorticortrophlc hormone on electrical activity of brain and on sensitivity to convulsion-mducmg agents Am. J. Physzol. 168,406 (1952).
The dmmal varlatlon of plasma cortlsol levels m depression
195
25. WAYNE H. L Convulsive seizures comphcatmg cortisone and ACTH therapy; chmcal and J. C[m. Endocr Metab. 14, 1039 (1954). electroencephalographx observations 26. CLEGHORN R A Hormones and humors Proc. 1st Int Congr. Hormonal Steromk, Vol. 2 Acad. Press, New York (1965) 27 Fox H. M and GIFFORIJ S. Psychological responses to ACTH and cortisone prehmmary theoretical formulation. Psychosom Med 15, 614 (1953) 28. LEVINES. Z Some clinical and metabohc responses of premature infants to pltmtary adrenocortxotropm (ACTH) admuustratlon, m Panel on Metabolism m Premature Infants, Stockholm, United Nations World Health Orgamzatlon, Infant Metabolism Seminar (November 1950) 29. HOEFER P F and GLASER G H Effects of pituitary adrenocortlcotroplc hormone (ACTH) therapy Electroencephalographlc and neuropsychlatnc changes m fifteen patients J Am. Med Ass. 143, 620 (1950). 30. ENGEL G L. In, Dlscusslon on psychloglcal responses to ACTH and cortisone by Fox H M. and GIFFORDS. Psychosom Med 15,614 (1953).
,1966,Vol
10, PP
189 to 195
Pergamon Press Lfd
Prrnted m Northern Ireland
THE DIURNAL VARIATION OF PLASMA LEVELS IN DEPRESSION*
CORTISOL
D. J. MCCLURE (Recemed 25 February 1966) DEPRESSIVE rllnesses are suitable for the study of adrenocortrcal acttvrty m relatron to emotion because they are common and the patrents are usually manageable without medrcatton for long enough to permtt chmcal observatrons and the collectron of laboratory data The findings of Board et al. [ 1,2] showed elevation of the 17-hydroxycorticosterord levels in the plasma of the more severe depressions, higher cortrsol values being found in the retarded depressrons than m the agitated depresstons. Gibbons and McHugh [3] reported a posrttve correlation between the severity of the depressive illness and the height of the plasma corttsol levels The existence of a circadian rhythm m the secretion of adrenal steroids has been estabhshed [4, 51. The cycle of the 17-hydroxycorttcosterord levels over a 24-hour period m normal subjects and under ordinary condtttons shows that the lowest concentratron of these steroids IS found between 10 00 pm. and 2.00 a m., from 2.00 a m. until 4 00 a m. there IS a gradual elevation, which IS then followed by a steeper rtse reaching maximum values m the region of 6.00 a m. to 8 00 a.m. After thus, there IS a sharp declme until noon and then a more gradual fall until 10 00 p.m. when the cycle starts anew. It was decided: (1) To measure the diurnal varratron m the levels of plasma cortrsol in psychiatric patients suffering from a psychotic depressive illness. (2) To determine whether these levels formed a characteristrc pattern for the psychotrc depressive group as a whole or whether there was an mdtvtdual pattern for each patient To consider posstble etrologrcal factors m the dtsturbed sleep rhythm which (3) occurs m the depressive psychoses.
MATERIAL The mvestlpatlon was carried out on seven psychlatrlc patients, two male and five female, with a mean age of 60 years and seven normal controls of comparable age and sex The activity of the . . . _. . adrenal cortex, with regard to the secretion ofcortlsol, IS llttle at&ted by the aging process in healthy persons of either sex [6, 71. Each patient was diagnosed as suffermg from a depressive psychosls [8,9]. The primary symptoms for the diagnosis were’ a mood of depresslon, a dmrnal mood change with exacerbation m the mormng, msomma with early mornmg awakening, and dlmmutlon of interest m the social environment Other symptomatic features were usually present mcludmg fatigue, selfblame, death wishes, loss of appetite, weight and libido, and disturbance m motor activity, either retardation or agltatlon. The diagnosis was made independently by two psychlatnsts, one of whom was the author. Added confirmatory data were supplied by the depressive scale of the Mmnesota Multi-Phaslc Personality Inventory (MMPI) and the Rorschach test, completed by a member of the psychology staff. All SubJects were considered sultable for electro-convulsive treatment The patients were receivmg no medlcatlon at the time of admlsslon to the study and had been free from all drugs for a rmmmum period of 4 weeks prior to It The difficulty m obtammg such cases IS obvious because most patients * From the Allan Memorial Institute of Psychiatry, McGill Umverslty, Montreal. 189
190
D. J. MCCLURE
are placed on medlcatton m-mediately after being seen by then own physician or by the psychtatrrst who carries out the mttlal Interview m order to tide the patient over untd he 1s admitted to hospital. This accounts for the small number of cases m the study Each candidate suitable for the mvesttgatron was placed on placebo three times dally and once at night for 48 hr During this time, blood was drawn over two consecutive 24-hour periods at intervals which would give most mformatton about the diurnal adrenocorttcal acttvrty, namely, 7 00 a m., 12 noon and 10 00 p.m METHODS Fifteen mllhhtres of venous blood were drawn at 6 45 a m , 11 45 a.m and 10 00 p m on two consecutive days into 20 ml test tubes containing hepann, then centrifuged and the plasma separated and frozen untd assayed The plasma cortlsol levels were determined by a slight modtfication of the dialysis method described by Murphy et al. [lo] This method measures both cortlsol and corttcosterone m the plasma, but since the amount of corttscosterone IS only about 1/13th that of cortnol, the results obtained here will be referred to as plasma cortlsol [ll]. The statistical analysts used m this experiment was that described by Wmer [12] for a two-factor expenment with repeated measures. In carrying through this analysis on the raw data, it was found that the parts pooled to form the denommators of the F-ratio lacked homogeneity due to the high values obtained from the patients at 7 00 a m. Therefore, the analysts was conducted on the logarithm to base 10 of the data and this time the parts pooled to form the denommators of the F-ratios were homogeneous. t-tests were conducted on those sources of variation that proved to be srgmficant. RESULTS The data for the mvesttgation on seven depressed patients and the seven normal sublects are shown on Table 1. The analysis of vartance table for this data IS given m Table 2. Examination of these results shows that there was a very highly slgmficant difference between the two groups of subjects (P c 0 0005, Table 2) The mean and standard error of all twenty-one values for the seven subJects was 27 8 f 2 7 ,ug/lOO ml plasma, whrle the corresponding values for the normal was 11 8 i 1 3 pg/lOO ml plasma (Table 3) There was also a very highly slgmficant dtfference due to diurnal vartatlon m the values (P < 0 0005, Table 2). Subsequent I-tests showed that there were stgmficant differences between the 7.00 a m and noon values (0 02 > P > 0 01, Table 3) and also between the noon and 10 00 p m values (0 01 > P > 0 001) It will be noted that the differences between the two groups was greater at 7 00 a m than at noon or at 10.00 p m. (Table 3). TABLE I.-PLASMA
Pattents
Normals
CORTISOL LEVELS (pg/lOO ml) IN NORMAL
Age
(yd
SUBJECTS AND IN DEPRESSED PATIENTS
Sex
1 2 3 4 5 6 7
F F M M F F F
48 62 70 71 56 64 48
29 00 34 00 31 00 34 00 53 00 61 00 34 00
20 50 1875 1925 1600 32 75 37 25 29 00
1875 1550 1250 1175 31 25 23 50 21 50
1 2 3 4 5 6 7
F M F F M F F
60 66 49 65 73 53 54
23 00 1700 16 50 22 50 17 50 15 50 1150
1400 13 50 13 50 16 50 900 11 25 8 00
500 2 75 3 25 600 6 00 9 50 5 00
700am
12 noon
10OOpm.
Sublect
The differences between the mean of values obtamed from samples taken at 7 00 a m and noon (9 9) was greater than those obtamed between noon and 10 00 p rn* (6 2) (Table 3) However. exammatton of the data m Table 4 shows that differences between the logarithm of the values at 10 bo p m and noon are bigger than those between 7 00 p m and noon. Thtsmteractton is apparently not statistically slgmficant if one apphes the conservative test, as descrtbed m the next paragraph The discrepancy between the values obtained m Tables 3 and 4 is due to the conversion of the raw values mto logartthms which reduced the larger numbers to a greater extent than it dtd the smaller ones. A graph of the raw values 1s shown m Fig 1 It IS obvious m this figure that dlfferences between patrents and normals were greater at 7 00 a m than at noon or 10 00 p m
The dmrnal variatton of plasma corttsol levels in depression TABLE 2.-ANALYSIS
OF VARIANCE TABLE FOR TWO-FACTOR
191
EXPERIMENT WITH REPEATED MEASURES
Sum of squares
Degrees of freedom
Variance estimate
Between SubJcCts A (Effect of depression) Subjects wmun groups
2 13080280 1 70323989 0 42756291
13 1 12
1 703239s9* 0 03563024
Wrthm SubJects B (Diurnal vartatron) AB B x subjects wtthm groups
1 69179551 1 30524173 0 14450158 0 24205220
28 2 2 24
065262087* 007225079t 0 01008551
Source
* Stgmficant at the 0 05 ‘A level t Srgmficant at the 2 5 % level.
TABLE ~-SUMMARY
Subjects
OF DEPRESSION x DIURNAL VARIATION INTERACTION
7OOam*
Patients Normals Mean:
12 noon
39 4 17 6 28 5
1000pm
Meant
19 3 54 124
27 8 11 8
24~8 123 186
Standard error f27 *13
* The mean value shown for a given time IS the mean of seven determmatrons. t The values shown m this column are the mean of twenty-one estrmatrons. $ The values shown m this row are the mean of fourteen esttmatlons
TABLE 4 -SUMMARY
Subjects
OF THE LOG VALUES OF DEPRESSION x DIURNAL VARIATION INTERACTION 12noon
700am.
1000pm
Total
Patients Normals
110579 8 6558
9 6219 75326
8.8287 48622
295085 210506
Total
197137
171545
13 6909
505591
45 t-
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FIG 1 Diurnal variatton in the plasma corttsol concentrations subjects. 4
1
IOwn
of normal and depressed
192
D. J. MCCLURE
The mteractton between the effect of depression and the diurnal variation was stattstmally slgmficant (0 025 > P > 0 01, Table 2) This level of stgmficance was reached when one used the dmrnal variation X SubJects withm groups error which in this analysis is less than the SubJects within groups error In short, the ordinary test led to a statlsttcally sigmficant result for the mteractlon but when repeated with the subjects wtthm groups error which was larger, the results do not quite achteve sigmficance (0 20 > P > 0 10, Table 2). DISCUSSION
The levels of plasma cortisol were very much higher in the psychotrcally depressed patrents than m the normal subjects. However, there were at least three factors m addition to the prrmary mood disturbance contrrbutmg to these initrally high values. They Included the stresses produced (a) by being admitted to hospital [ 13, 141; (b) by undergoing the procedure of vempuncture and (c) the absence of any sedative medrcatron which would lower the hormone values [16, 171 The role played by these factors IS probably only a mmor one but they should be taken mto consrderatron when evaluatmg the differences between the normal subjects and the depressed patients. Board et al [2] hmitmg their investigatron to exammmg morning samples of blood, showed that raised levels of adrenocortical hormone occurred in depressed patients at thus time of day. The present results indicate that the hrgh cortrsol levels found m depressive illness extend throughout the 24-hour period with the highest A good correlatron was found between the values occurrmg m the early morning. severity of the depression and hormone levels m the plasma (Table 5), which IS m agreement with the work of Gibbons and McHugh [3]. The two cases (Numbers 6 and 5) with marked subjective and motor retardation had higher levels than the others, all of whom were agitated. This supports the findings of Board et al. [2]. TABLE
~--PLASMA
Clinical rating
++++ +++ +-I+ 0
CORTISOL LEVELS @g/l00 ml) ACCORDING CLINICAL RATING
Number of estimations 21 6 9 6 9
TO
Mean and standard error 27 8 200 13 9 155 105
+ f * k $-
2 7 ,ng/lOO ml 142~g/lOOmI 7 1 ,ug/lOO ml 106,@00ml 53,ug/lOOml
No specrfic dmrnal plasma cortrsol curve pathognomomc of psychotic depressive illness was found. The cortisol levels varied at different times of the day m all patrents m a similar fashion to that found in normal subjects wrth the highest level present m the morning, the next highest at noon, and the lowest m the evenmg. This suggests that m depressed patients, the same central mechanism which controls the normal diurnal rhythm of cortrsol secretion is stall operating, but that It IS greatly accelerated, causing a srgmficant increase in the adrenocortrcal actrvlty whrch m turn produces the hrgh perrpheral blood hydrocortrsone levels. The work of Grbbons [18], usmg radroactive cortrsol to determine the adrenocortrcal secretion rate, confirmed this increase m adrenal activity m depressed subjects and rt demonstrated that there was a hrgh correlatron between the elevated plasma cortlsol levels and the cortrsol secretion rate Patients The sleep disturbance m psychotic depression has a characterlstrc pattern.
The diurnal vartatlon of plasma cortlsol levelsIn depresslon
193
usually state that they are able to get to sleep wlthout much difficulty but that they awaken m the early hours of the morning and cannot get back to sleep again. All seven depressed cases m the study had this typical disturbed sleep rhythm. A number of mvestlgators have put forward explanations for this sleep disturbance For example, Swift and Ehthorn [19] postulated that there was a primary hypothalamic disturbance which resulted m an mverslon of the sleep rhythm tending to produce increased wakefulness at night. Oswald et al. [20], after taking contmuous nocturnal encephalographic recordings, measurmg eye movements and bed movements, reported that they failed to reveal any characterlstlc abnormality of sleep m patients with melanchoha other than an excess of wakefulness. Another explanation might be that the primary disturbance m mood sets off a cham of events mvolvmg over-activity of certain hypothalamic functions, causing an increased output of ACTH which m turn produces over-activity of the adrenal cortex, leading to an elevation of the plasma cortlsol levels. Even though the markedly elevated morning values decline during the day, the 10 00 p m. evening levels, are still very high. In the diurnal cycle, the increase m the secretion of cortlsol commences about 2.00 a m. so that the already high plasma cortlsol levels are further increased during the early hours of the morning and this comcldes with the period of early morning awakening and increased wakefulness. There 1s a significant amount of evidence from animal experiments [21-231 and from clinical data [24-261 to support the view that cortlsol-like steroids m large quantities increase bram excitability. They also appear to interfere with the normal sleep rhythm. For example, Fox and Glfford [27] found increasing wakefulness to be one of the principal effects of ACTH and cortisone given to a variety of medical patients; and Levine [28] observed wakefulness in premature infants who were given dally injections ofACTH. The electroencephalographic findings [29] which reflect the neurophysiological changes produced by an excess of adrenal steroids, show a sigmficant amount of slow wave activity and increased sensitivity to hyperventilation. Whether the effects of these steroids on brain excltablhty are found under physlologlcal and pathological condltlons 1s still undetermined. Nevertheless, the evidence, according to Engel [30] 1s very suggestive that these hormones 1s excess do have a direct effect on brain function. It seems reasonable, therefore, to suggest that the very high plasma cortlsol levels found in psychotically depressed patients exert a stlmulatmg and excitatory action on the brain to produce the symptoms of early morning awakening or increased wakefulness found m this condition. SUMMARY The diurnal variation of plasma cortisol levels was studied in fourteen subjects, seven psychotically depressed patients and seven normal persons of comparable age and sex. The cortisol levels were higher in the patients and remained high throughout the 24 hr. The highest values occurred in the morning and the lowest at night. Good correlation was found between the severity of the clinical depression and the levels of plasma cortisol. Higher values were found in the retarded than in the agitated depressions. When the diurnal plasma cortisol values were plotted graphically, they did not form a pathognominic curve which would be of diagnostic use in psychotic depressive illnesses. Instead, each patient formed then own individual curve. The central
194
D. J. MCCLURE
mechanism controlling the normal diurnal rhythm of cortisol secretlon appeared to be still operating but greatly accelerated. It IS hypothesized that cortisol 1s a good indxator of the severity of psychotic depression and that it may also be responsible for the early mornmg awakenmg which occurs m this illness. Acknowledgements-I particularly wish to thank Professor R A. Cleghorn, whose supervtston and gtudance were constant source of sttmulatton throughout thts work Dr. B Grad helped with the statist& data. The study was made possible by a Fellowshtp from the Medical Research Counctl of Canada.
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repeated measures. McGraw-Hnl, New York (1962).” A 13 MASON J W . SACHARE. J . FISHMANJ R . HAMBURGD A and HANDLONJ H. Cortlscosterold responses to hospttal adnussron. Archs. Gkn. Psychrat 13, 1 (1965) system, m Recent Progress m 14 MASON J W Psychological influences on pmntary-adrenalcortlcal Hormone Research. ed G PINCUS.vv. 345-389 Academic Press. New York (1959) 15 CLEGHORNR A , and GRAHAMB F.‘S’tudles of adrenal cortical ac&ty m psychdneurotlc subjects. Am J. Psychzat. 106, 668 (1950) 16. SHIBUSAWAK , SAITOS , FUKADA M , KAWAI T., YOMATOH and TOMIZAWAK Inhlbmon of the hypothalamus-neurohypophyseal neurosecretlon by chlorpromazme. Endocr Jap 2 (3), 189
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17 Co TUI F , BRIN~~ZERW , ORR A. and ORR E. L. Effect of chloropomazme and of reserpme on adrenocortlcal function Psychzat. Q. 34,47 (1960) 18 GIBBONSJ. L Corttsol secretion rate m depressive illness. Archs. Gen Psychzat 10, 572 (1964) of depression Proc 3rd 19. SWIM N and ELI~HORNA. An exnenmental annroach to the nroblem I Wld Conf Psychlat 2, 1372-1376 11962) _I 20 OSWALD I. BERGERR. J . JARAMILLOR A.. KEDDIEK M G . OLLEY P G and PLUNKE~~G B. Melanchoha and barbtturates A controlled EEG, body and’eye movement study of sleep Br. J Psychzat 109, 66 (1963). 21. W~~DBURY D M. Adrenal cortex and central nervous system Pharmac Rev 10, 276 (1958). 22. DE SALVA S J , HENDLEYC. D. and ERCOLI N Acute effects of ACTH and cortisone on brain excnablhty. Archs. Znt Pharmacodyn Ther 100, 35 (1954) 23 PINCUSJ B , NATELSONS and LUGOBOYJ. K Effect of epmephrme, ACTH and cortisone on citrate, calcmm. Proc Sot Exp Bzol Med 78, 24 (1951) 24 TORDA C and WOLFF H G Effects of various concentrations of adrenocorticortrophlc hormone on electrical activity of brain and on sensitivity to convulsion-mducmg agents Am. J. Physzol. 168,406 (1952).
The dmmal varlatlon of plasma cortlsol levels m depression
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25. WAYNE H. L Convulsive seizures comphcatmg cortisone and ACTH therapy; chmcal and J. C[m. Endocr Metab. 14, 1039 (1954). electroencephalographx observations 26. CLEGHORN R A Hormones and humors Proc. 1st Int Congr. Hormonal Steromk, Vol. 2 Acad. Press, New York (1965) 27 Fox H. M and GIFFORIJ S. Psychological responses to ACTH and cortisone prehmmary theoretical formulation. Psychosom Med 15, 614 (1953) 28. LEVINES. Z Some clinical and metabohc responses of premature infants to pltmtary adrenocortxotropm (ACTH) admuustratlon, m Panel on Metabolism m Premature Infants, Stockholm, United Nations World Health Orgamzatlon, Infant Metabolism Seminar (November 1950) 29. HOEFER P F and GLASER G H Effects of pituitary adrenocortlcotroplc hormone (ACTH) therapy Electroencephalographlc and neuropsychlatnc changes m fifteen patients J Am. Med Ass. 143, 620 (1950). 30. ENGEL G L. In, Dlscusslon on psychloglcal responses to ACTH and cortisone by Fox H M. and GIFFORDS. Psychosom Med 15,614 (1953).