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Blood Platelet Aggregation and Personality Traits a

Dr. C. David Jenkins Ph.D. , Dr. Georgelle Thomas b

c

Ph.D. , Dr. Donald Olewine Ph.D. , Dr. Stephen J. d

e

Zyzanski Ph.D. , Dr. Michael T. Simpson M.D. & Dr. Curtis G. Hames M.D.

f

a

Department of Behavioral Epidemiology in the Division of Psychiatry , Boston University School of Medicine , Boston, Massachusetts, USA b

Psychology at Georgia Southern College , Statesboro, Georgia, USA c

Biology , Georgia Southern College , USA

d

Psychiatry in the Department of Behavioral Epidemiology in the Division of Psychiatry , Boston University School of Medicine , USA e

Department of Medicine , University of Alabama Medical Center , Birmingham, Alabama, USA f

Evans County Health Department , Claxton, Georgia, USA Published online: 09 Jul 2010.

To cite this article: Dr. C. David Jenkins Ph.D. , Dr. Georgelle Thomas Ph.D. , Dr. Donald Olewine Ph.D. , Dr. Stephen J. Zyzanski Ph.D. , Dr. Michael T. Simpson M.D. & Dr. Curtis G. Hames M.D. (1975) Blood Platelet Aggregation and Personality Traits, Journal of Human Stress, 1:4, 34-46, DOI: 10.1080/0097840X.1975.9939551 To link to this article: http://dx.doi.org/10.1080/0097840X.1975.9939551

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BLOOD PLATELET AGGREGATION AND PERSONALITY TRAITS

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C. DAVID JENKINS, Ph.D., GEORGELLE THOMAS, Ph.D., DONALD OLEWINE, Ph.D., STEPHEN J. ZYZANSKI, Ph.D.. MICHAEL T. SIMPSON, M.D., CURTIS G. HAMES, M.D. Changes in blood platelet aggregation to at tempt to derive clinical implications ma-v precipitate episodes of arterial 06- ,f;om this exploratory work, but some clusive diseases. Little is known. implications .for the design of j k t u r e however. regarding the influence o/' research are discussed. psychological traits, emotional statrs Blood platelet aggregation plays an and other behavioral stressors o n important but incompletely specified role platelet aggregation phenomena. in arterial occlusive diseases, including This study examined 46 health-v COImany instances of coronary heart dislege men at rest and afier submaximal ease and stroke. Recent clinical and treadmill exercise. A ssociations we re epidemiologic studies have implicated found between the duration of platelet personality and behavior as among the aggregation and a number of scores spectrum of risk factors for coronary .f;om the California Psychological Invendisease,' and possibly also for stroke. ' tory and self-administered anxiety Thus it would seem valuable to explore scples. T h e more socially adequai'e, the interrelations of personality and poised and dominant persons - those on the one hand, and blood behavior, with more mature ego development arid less ovei? anxiety - had platelets with platelet aggregation, on the other. The more prolonged aggregation reactions to present paper is a preliminary effort in the in vitro introduction of'noradrenulin. this direction. An earlier report by this Irreversible aggregation of' platehts group described relations between occurred more regularlv to lower in platelet aggregation and the coronaryvitro concentrations of noradrenalin in prone behavior pattern.s platelet samples drawn f i o m subjects METHODS who werp less anxious and tended to be more rigidly defensive. I t is premature A pilot study served to acquaint the

Dr. Jenkins is Director of the Department of Behavioral Epidemiology in the Division of Psychiatry at Boston University School of Medicine in Boston. Massachusetts.

Dr. Zyzanski is Associate Professor of Psychiatry in the Department of Behavioral Epidemiology in the Division of Psychiatry at Boston University School of Medicine.

Dr. Thomas is Associate Professor of Psychology at Georgia Southern College in Statesboro, Georgia.

Dr. Simpson is Resident in the Department of Medicine at the University of Alabama Medical Center in Birmingham, Alabama.

Dr. Olewine is Professor of Biology at Georgia Southern College.

Dr. Hames is Chairman of the Evans County

34 Journal of Human Stress

Health Department in Claxton, Georgia.

December. 19 75

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JENKINS, THOMAS, OLEWINE, ZYZANSKI, SIMPSON and HAMES experimenters with some of the problems of studying these biological parametersb It set the stage for more refined methodology and laboratory technique for the present research. An intensive study was conducted of 46 male college student volunteers attending summer school. Both graduate and undergraduate students participated, their average age being 24.5 years. Sixty milliliter blood samples were obtained using 18-gauge needles. Specimens were drawn from subjects who were resting, again immediately after treadmill exercise to a submaximal criterion (about 85 percent of maximum capacity) and finally after a 15-minute recovery period. The phenomena of platelet aggregation and the release of platelet contents generally are considered to play a primary role in arterial thrombus formation. In addition, the “encrustation theory” of atherogenesis implicates platelets in plaque formation. The conflicting evidence on these issues recently has been reviewed.’ Platelet aggregation was studied in vitro by the optical density method of Borna and O’Brien.q Citrated whole blood was centrifuged to obtain platelet-rich plasma. The platelet-rich plasma was stirred at 37 C. with a magnetic stirrer while percent transmission of light through the suspension of platelets was determined on an EEL photometer and recorded on a Honeywell 0-10 mv recorder. Aggregation or “clumping” of the platelets results in increased transmission of light through the initially turbid suspension. One measure of platelet aggregation is duration of the aggregation reaction. O’Brien9 terms this “reaction time” and defines it as the duration in seconds from the addition of the aggregation agent, such as adrenalin or noradrenalin, until the first phase of ag-

December, 1975

gregation is completed - that is, until cessation of the increase in light transmission through the stirred platelet-rich plasma. A characteristic graph produced by the laboratory system is presented as Figure 1, with the operational definitions of several key variables indicated. Measurements of platelet aggregation are influenced by the number of platelets in the plasma. To permit comparison of platelet aggregation between individuals with different plasma platelet counts, each measurement was adjusted mathematically by the method of O’Brien to a standard concentration of 400,000 platelets per cubic millimeter.’O Platelet determinations were done immediately after drawing the blood in a room adjacent to the treadmill. The aggregation reaction in response to adrenalin and noradrenalin, in the concentrations used here, runs its course and stabilizes at a given level of light transmission, but after a few seconds this usually is followed by a second and irreversible clumping of platelets which results in virtually complete clearing of suspended particles from the plasma. This latter phenomenon of irreversible aggregation is referred to by O’Brien as ”second slope” (from its graphed representation as shown in Figure 1) and is thought to be the result of release of adenosinediphosphate (ADP) from the granules within the platelets. We have recorded it here as being either present or absent for each plasma sample. The amount of catecholamine introduced by pipette was many times the concentration which would occur physiologically (i.e. 0.1 cc of 1 x M for adrenalin and 0.1 cc of 1 x lo-‘ M for noradrena h ) . .Samples not responding with irreversible aggregation to the initial respective concentration were tested with Journal of Human Stress

35

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PLATELET AGGREGATION

2nd

80

r

I

slopr

I

2 3 Minutes

TYPICAL ADRENALIN OR NORADRENALIN-INDUCED PLATELET AGGREGATION

a second stronger concentration. Nevertheless, only about three-fourths of the men showed the expected “second slope” or irreversible aggregation reaction. It was recognized that irreversible aggregation is present in most persons but that taking a variety of drugs can block the reaction.” To eliminate this source of interference with aggregation in this study, all subjects were warned strongly against taking aspirin or any other medications during the week prior to their participation in this study. In the case of headache or other discomfort, study subjects were asked to contact one of the principal investigators for alternative medication which would not affect the platelets. Exercise, diet and amount of sleep were recorded in a diary for the week preceding participation in the study as an additional means of determining unusual behaviors or sharp changes in behavior which might introduce artifact into the biological variables under study. Further questioning on the day of ex-

36 Journal of Human Stress

amination satisfied the field investigators that known major interferences with platelet reactions had been avoided successfully by the study group for the week prior to the morning each man was studied. During the same week as the treadmill exercise and drawing of blood samples, the subjects completed a number of psychological tests, including the California Psychological Inventory (CPI).12This test consists of 480 truefalse items arranged into 18 standard scales designed to measure personality traits manifested by normal people in everyday situations. These scales were developed by empirical methods which take into account such problems as the tendency of subjects to try to portray themselves in a desirable light and the common “blind spots” many persons have concerning their own behavior. In addition to the CPI, three anxiety scales were administered. Spielberger’s StateTrait Anxiety Inventory (STAI) consists of a series of 20 items which the responDecember, 1975

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JENKINS, THOMAS, OLEWINE, ZYZANSKI, SIMPSON and HAMES dent answers in terms of the way he or she usually feels (“Trait”). The same items are re-administered in terms of how one feels “right now” for the “state” measure.’) In our study, this was done in the minutes before the first blood sampling. The third scale, Bendig’s short form of the Taylor Manifest Anxiety Scale, is made up of 20 items from the Minnesota Multiphasic Personality Inventory. The validity of this subscale has been supported by several studies.“. I s Because of the lack of knowledge as to which of the several platelet aggregation indices might be most predictive of cardiovascular pathology, and because of a total lack of theory regarding the possible interactions between platelet phenomena and traits of the sort measured by the CPI, a structured research design was not possible. Instead, a search for correlations and group differences was made. The Spearman rank order correlation coefficient, rho, was selected as the measure of association, inasmuch as distribution of some of the biological variables departed from normality due to several outlying values. The Kendall rank order correlation, tau, also was calculated but is not presented because it is expressed in its own metric which is not comparable to the more familiar values of the Pearson and Spearman coefficients. The Kendall tau has the advantage that it can be used in a partial correlation procedure, but no procedure is available for testing the statistical significance of the resulting statistic. Nevertheless we used the Kendall procedure to deal with the issue of the built-in correlation between resting values of platelet indices and the change measure derived by subtracting the resting from the post-exercise determination. December. I9 75

For the more normally distributed psychological scale scores, t-tests also were used. Because of the small sample size, the reduced variability on some measures and the exploratory nature of the study, notice will be taken of findings at the P = .10 level of statistical significance as well as the usually observed P = .05level. R ESULTS The reactions of blood platelets in v i m to small infusions of adrenalin and noradrenalin were studied immediately before and immediately after submaximal treadmill exercise. Durations of the aggregation reaction of platelets from resting blood samples to added adrenalin in this artificial system ranged from 39 to 88 seconds, with a median of 57 seconds. One additional man with an outlying value of 198 seconds was excluded from these analyses. This aggregation variable for adrenalin was correlated significantly only with the Bendig anxiety score (rho = -35; P = .05).Persons scoring higher on anxiety had platelets with the shorter durations of the aggregation reaction. In addition, there is a correlation of .28 (P = .05) between the score on the Anxiety State Scale and the increase in duration of the aggregation reaction to adrenalin in vitro between resting and post-exercise measures; but this may be attributable statistically in part to the briefer reactions observed at rest among the more anxious subjects (by Bendig’s Scale). The duration of the aggregation reaction of blood platelets to noradrenalin in this group averaged 57.8 seconds, with a standard deviation of 9.7 seconds. The duration correlated significantly (rho = .30; P = .05)with the concurrent level of serum noradrenalin. The aggregation reaction manifested many strong connec-

+

Journal of Human Stress 37

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PLATELET AGGREGATION tions with psychological characteristics (Table 1). No fewer than 9 of the 21 psychological scales showed statistically significant correlations with the duration of platelet aggregation to infused noradrenalin in vitro. Dividing tlhe 46 values for this variable at their median yielded a longer duration group with a range of 82 to 56 seconds, and a shorter duration group with a range of 55 to 36 seconds. Young men whose platelets (sampled at rest) had the capacity for prolonged aggregation reactions to noradrenalin scored higher on CPI scales which reflect such traits as dominance, sociability, enterprise, intellectual efficiency, achievement (through cooperation and conformity), seeking for status, poise, social effectiveness and self-confidence. This profile of differences is displayed in Figure 2. These “prolonged aggregators” also scored significantly lower on the Anxiety Trait Scale and the Bendig Anxiety Scale. The Discussion presents clinical inferences regarding the psychological implications of these test profile dif-

~~~

ferences between subjects with longer and shorter durations of aggregation. Noradrenalin reaction time of platelets tested after exercise increased modestly in duration on the average compared to resting samples. (Mean change was +4.1 seconds; standard deviation was 14.7). Men whose platelets had short durations of reactions at rest tended to show greater increases than those with longer durations. Some with longer initial durations even showed a decrease after exercise. The correlation of resting noradrenalin reaction time to change in this parameter after exercise was -.46. It should be noted in Table 1 that of the nine scales correlated with aggregation reaction at rest, five were correlated in the opposite direction (two significantly), with change of aggregation time after exercise. This change in aggregation was not correlated significantly with resting level, post-exercise level, or the amount of change in serum noradrenalin. This and other change variables are statistically dependent upon the variables

~~

TABLE 1 Spearman Rank-Order Correlation between Selected Psychological Scores and Duration of Platelet Aggregation to Noradrenalin in vifro. Duration of Aggregation Reaction At Rest

Psychological Scales CPI - Dominance CPI - Capacityfor Status CPI - Sociability CPI - Social Presence CPI - Well-Being CPI - Achievement thru Conformity CPI - Intellectual Efficiency

.32 .33 .41

- .27

- .40 - .47 .26

-

___ - .24

- .50

STAl - Anxiety Trait Bendig Anxiety Scale Note 1: Rho greater than 46 subjects.

.41

.40 .4a .38

Change Induced by Exercise

- .47

?

2 8 is significantly different from .OO at p = .05 for this sample size of

Note2: The range of durations of platelet aggregation to noradrenalin using this method in this group was from 36 to 82 seconds with the median being 56 seconds.

38 Journal of Human Stress

Deceni ber, I9 75

JENKINS, THOMAS, OLEWINE, ZYZANSKI, SIMPSON and HAMES PROFILE SHEET FOR CALIFORNIA PSYCHOLOGICAL INVENTORY Plots of Mean Scores for College Men whose Blood Platelets had Prolonqed Duration o f Aggregation in Response to Noradrenalin in Vitro

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VS. Shorter

- - - - P men wkh prolongedplatalet aggregation

-23 men wlth ahorter dwatlon of platelet aggregation *Signlflcance of difference by t-teat. Pdd.

Sh.*l

Multlvarlateteat: Hotelling P for all 18 scales: P = ,073

Copyrlghl by Caniultmp R y ~ h o 1 ~ bPr*ss.lnc l1 ,PoloAllO,Ca1tfomm A l l r,phts ns.rred

involved in their calculation, in the present case, the corresponding initial resting value. It is not established for platelet aggregation whether absolute levels or reactivity of these in v i m indices (or neither) are more relevant to thrombogenesis in vivo. Thus, one cannot state which of these two measures is secondary to the other. In any event, if the change value is well predicted by the resting value, gathering this second measurement does not add new information - a finding of practical importance. Pursuing this point, we calculated Kendall partial rank order correlations for all instances where an exerciseinduced platelet change was significantly December, 1975

associated with a psychological score. The relations of the Sociability and Capacity for Status scores to the change in duration of aggregation to noradrenalin were lowered only slightly by the partialing procedure. This suggests that both initial duration of the platelet response and its reactivity are independently associated with these two psychological characteristics. All other correlations with change scores were reduced to small absolute size by the partialing procedure. As indicated earlier, statistical significance tables and formulae are not available for the partial tau.I6 Level of physical fitness has been Journal of Human Stress

39

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PLATELET AGGREGATION found associated with platelet reactivity in other studies. Physical fitness was measured in terms of METS, an index of oxygen consumption based on treadmill performance. Almost all of the sample achieved METS scores of 9 to 11 on the treadmill. None were below 7 or greater than 12. This measure was not significantly correlated either with platelet variables or these psychological scores, thus ruling out the possibility that the psychological findings were secondary to associated differences in physical fitness. The intensity of the aggregation reaction was measured by the graphed slope of the change in light transmission through the blood specimen. Rapid, extensive aggregation and precipitation of the platelets from the stirred mixture results in substantial increase in light transmitted and a high reading on “slope.”8 “Slope” was calculated as the change in percent transmission of light per minute during the period of most rapid change. This showed only owasional and inconsistent correlations with the psychological scales administered and these were interpreted as most likely being due to chance. All three blood samples (resting, post-exercise and recovery) from each individual were challenged with two c‘oncentrations each of adrenalin and noradrenalin. The persons who consistently showed irreversible aggregation (“second slope” in Figure 1) to the more dilute concentration of amine are labeled “easy aggregators” in Table 2. Those who did not show irreversible aggregation even with a stronger concentration of adrenalin are listed as resisting aggregation. Only a few men resisted aggregation completely to the concentrations of noradrenalin used. Therefore, for that lower portion of Table 2, all per40

Journal of Human Stress

sons not regularly showing irreversible aggregation were grouped together and contrasted against the “easy aggregators” ke., those uniformly showing irreversible aggregation to 0.1 cc of 1 x M of noradrenalin). Table 2 shows that young men whose platelets regularly aggregated irreversibly to the initial concentrations of adrenaline in vitro were significantly more rigid and more guarded in their demeanor. Those whose platelets aggregated easily and irreversibly when challenged in vitro with noradrenalin were significantly less anxious and also tended to be more rigid, formal, dominant and self-reliant. The consistent trend for “easy aggregators” (in response to either amine) to have low flexibility scores suggests t h a t psychological rigidity may be a concomitant of a lower threshold for irreversible platelet aggregation. DISCUSSION

This exploratory project quantitatively has studied psychological traits and platelet aggregation phenomena in young men before and after strenuous exercise. Twenty-one psychological scale scores and a variety of platelet measures were entered into the statistical analyses here reported. Because of the substantial number of correlations calculated, a few of the significant findings may be attributable to chance. This underscores the need for replication of the work before psychological generalizations can be made. The relatively large number of significant findings involving the reaction of platelets to noradrenalin and the consistent psychological syndrome portrayed by the findings lend particular credence to that portion of the findings, however. Seven CPI scales showed significant December. 1975

JENKINS, THOMAS, OLEWINE, ZYZANSKI,SIMPSON andHAMES TABLE 2 Differences of Mean Psychological Scores Between Young Males With and Without IrreversiblePlatelet Aggregation

Scale -

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CPI - Flexibility’

Adrenalin Challenge Resisting Aggregation

8.2 (N=15)

t -

P. -

2.38

.05

t

P.

28.3

1.73

.10

10.0

1.88

.10

36.8 (N=21)

2.06

.05

11.5

(N=121

Noradrenalin Challenge Easy All Aggregators Others CPI - Dominance CPI - Flexibility STAl - Anxiety State’

31.4 (N=19) 8.1 (N=19) 31.2 “-16)

1. Reducedsample size due to exclusion of an intermediate group with inconsistentpresence and absence of second stage. 2. Reduced sample size due to some subjects not having completed the State-Trait Anxiety Index.

rank order correlations with duration of the platelet aggregation reaction to noradrenalin (Table 1). Long and short aggregation groups differed by t-test on all seven of these, plus one other: Tolerance (Figure 2). Dominance, Capacity for Status, Sociability, Social Presence, and Well-Being all reflect poise, ascendency, self-assurance, and personal adequacy (Gough’s Class I Scales.)” The first four of these load highly on a general factor which Megargee describes as representing extroversion and interpersonal effectiveness.” The remaining two scales involved here are measures of intellectual efficiency and achievement potential. Together with the Well-Being scale they seem to represent an element of “potential for success” and general positive adDecember. 1975

justment (implied by Megargee’s Factor 1.P’ Correlations have been reported between the Repression-Sensitization scale,18a measure of one style of defensiveness, and the four CPI scales: Sociability, Well-Being, Achievement through Conformity, and Intellectual Efficiency, with high scorers on the CPI scales using the most repressive defenses.l 7 This interpretation is consistent with the observations here that high scores on two anxiety scales (a sign of the breakdown of repressive defenses) are negatively associated with the duration of the noradrenalin platelet reaction whereas the CPI scales are positively associated.17+.z12 The authors are not experienced in the clinical interpretation of CPI profiles, Journal of Human Stress 43

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PLATELET AGGREGATION and therefore sought out the most qualified consultation possible. Professor Harrison Gough, the author of the Ca lifornia Psychological Inventory. generously agreed to interpret the profiles in Figure 2 blindly. He was told only that the lines represented two groups of college and graduate school men, average age 24.5, who differed in the “reactivity of blood platelets,” but no further particulars were provided regarding how they differed. The pertinent sections of Professor Gough’s profile interpretation follow: . . . These two profiles are not all that different from each other, or from [those ofj college-educated men in general . . They should therefore be interpreted as two variants of a basic underlying pattern. A key problem in both profiles is a sense of personal effectiveness and talent pitted against a vaguely troubled feeling of unease and disaffection regarding contemporary life and trends. “A second observation is that both profiles reveal difficulties in the domain of impulse management, i.e.. in developing socially acceptable methods of expressing aggressive drives. Either profile, but particularly . . . [the lower one], carries the danger of a damaging breakthrough of negative impulse, whether directed toward others or vented inwardly in the form of rage and selfdefeating behavior. “While both profiles appear to reflect personality patterns still in a state of development . . . the major difference is that the higher profile has made a better start toward adequately resolving its problems. The lower profile group is more conflicted and may be running out of time in which to achieve a dynamically workable . . . [social emotional adjustment].” “Mechanical summing” of t h e “

.

44 Journal of Human Stress

characteristics of the significant CPI scales suggests that healthy young men with longer aggregation reactions are socially more adequate, more poised, dominant and intellectually capable, and more effective repressors of their anxiety. Professor Gough reminds us that the profiles are really not too different from each other. Nevertheless he points out that the group with shorter aggregation reactions has made less progress toward mature ego development, harbors more unresolved conflicts, and carries more risk of a damaging breakthrough of strong negative impulses. An early report on the same study group showed no significant association between measures of the Type A behavior pattern and duration of platelet aggregation to noradrenalin. Men with higher Type A, Speed and Impatience, or Hard-Driving scores, however, had significantly shorter aggregation reactions to adenosinediphosphate (ADPhS Thus, two psychological risk factors to coronary disease, anxiety-neuroticism and the Type A behavior pattern, were associated in this sample with shorter durations of aggregation to in vitro reagents. Essentially, these same psychosocially ineffective and vulnerable men (having shorter platelet aggregation reactions at rest) experienced a greater increase (or a lesser decrease) of the duration of their platelet reactions after exercise stress than was true for the more socially effective, achieving and resilient men. Anxiety also influenced the length of the aggregation response to in vitro adrenalin, with platelets from more anxious subjects having the shortest reaction at rest, but manifesting the greatest increase in length of reaction after exercise stress. As explained earlier, greater postexercise increases are correlated with December, 1975

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JENKINS, THOMAS, OLEWINE, ZYZANSKI, SIMPSON and HAMES shorter durations of aggregation at rest. Only for ambitious, outgoing and active persons (with high sociability and high capacity for status scores) can the psychological association with the amount of change be considered to be independent of the finding for resting levels. The phenomenon of a readily precipitated second and irreversible aggregation reaction following in vitm challenge with adrenalin or noradrenalin was associated with a less anxious, more assertive, more rigid style of behavior. This same phenomenon previously was reported to be associated with greater ‘tendencyto speed and impatience.s It is risky to speculate on the possible clinical implications of these platelet findings. The relation of O’Brien’s in vitm system to in vivo arterial platelet clumping has not been clearly established. According to the evaluative review by Genton, et al,7 a variety of measures of platelet adhesivity to a standard glass surface, of platelet electrophoretic mobility, and of platelet turnover have failed to discriminate patients with stable coronary disease from normal persons. Less clinical research has been done with the Born-O’Brien aggregation method used here, and Genton, et al, indicate that aggregation measures may not correlate well with adhesivity measures. This implies a need for additional independent testing of platelet aggregation methods in controlled studies of coronary disease patients. If one presumes that psychosocial risk factors for coronary disease deliver their pathogenetic impact at least partially through platelet phenomena, one would expect to find an association between psychosocial and platelet variables. The platelet phenomena might operate by increasing atherosclerotic plaque formation and/or by precipitating arterial December, I975

thrombi7 Only if the in vitm platelet procedure taps the more relevant of these processes could a clinically meaningful chain be constructed from psychosocial variables to platelet measure to cardiovascular pathology. In the present study, one might hypothesize that longer and more precipitous aggregation reactions and/or stress-induced changes in those directions would be associated with psychosocial risk factors to coronary disease and stroke, such as greater tendencies toward anxiety and neuroticism (evidenced by high anxiety scores and low scores on selected CPI scales). In fact, paradoxical findings emerged: Less robust emotional adjustment, and‘ presumably a greater propensity to reactions of anxiety and neuroticism under crisis conditions, were associated with shorter aggregation reactions at rest to one precipitator, noradrenalin, but not systematically to two others, adrenalin and ADP. However, these same men with problems of adjustment showed a relative increase in duration aggregation after exercise stress compared to their better defended colleagues. A parallel pattern of findings emerged for resting durations and changes therein in reaction to ADP for persons high on the Type A behavior patterms It would be very revealing to measure the platelet reactions of these groups after psychosocial stress. We are left with the question of whether platelet reactivity at rest, or after exercise, or neither has greater clinical implications, as well as the question of whether interactions of variables in this selected young sample parallel those in persons at more immediate temporal risk of clinical arterial occlusive disease. Journal of Human Stress 45

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PLATELET AGGREGATION The next research efforts should be addressed to exploring whether these associations are present in patients with varying degrees of atherosclerosis and varying histories of arterial thrombus formation. This would extend knowledge regarding the remainder of the hypothesized “chain” (above) and rriight convey further understanding of the linkages between psychological characteristics, human stress and cardiovascular disease which have been suggested by epidemiologic studies. This work was supported by USPHS Grant No. HL 03341 to Evans County Health Department, Claxton, Georgia, by Research Grants from the American Heart Association and the North Carolina Heart Association to the Univerrity of North Carolina School of Public Health (Dr. Jenkins). and by USPHS Grant No. HL 15399 to the Department of Behavioral Epidemuology. Boston University School of Medicine. The authors extend their thanks to Professor Harrison Gough. of the Institute of Personality kssessment and Research, University of California at Berkeley, who provided interpretations of the psychological test profiles: to Dr. Frank Ramsey. of Georgia Southern College, for assistance with the field work: and to David E. Kellogg who assisted with computer analysis of the data.

INDEXTERMS blood platelets, cardiovllscalar diseases, personality, psychological teats,stress.

REFERENCES Jenkins, C.D. “Psychologic and Social Precursors of Coronary Disease,” N. Engl. J. Med.. Vol. 284. 1971, pp. 244-255. pp. 30731 7. 2. Rosenman. R.H., M. Friedman, R. Straus, C.D. Jenkins, S.J. Zyzanski, and M. \Yurm. “Coronary Heart Disease in the Western Collaborative Group Study: A Follow-up Experience of 4% Years.” J. Chronic Dis.. Vol. 23, 1970, pp. 173-190 3. Adler. R.. K. MacRitchie, and G.L. Engel. “Psychologic Processes and Ischemic Stroke (Occlusive Cerebrovascular Disease). I . Observations on 32 Men with 35 Strokes,” Psychosom. Med., Vol. 33, 1971, pp. 1-29. 4. Gianturco, D.T., M.S. Breslin, A. Heyman, W.D. Gentry. C.D. Jenkins. and B.H. Kaplan. “Personality Patterns and Life Stress in

1.

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Journal of Human Stress

Ischemic Cerebrovascular Disease,” Stroke. Vol. 5,1974, pp. 453-460.

5. Simpson. M.T.. D.A. Olewine, C.D. Jenkins, F.H. Ramsey, S.J. Zyzanski. G. Thomas, and C.G. Hames. “Exercise-Induced Catecholamines and Platelet Aggregation in the Coronary-Prone Behavior Pattern.” Ps.vchosom. Med.. Vol. 36. 1974. pp. 476-487. 6. Simpson, M.T.. C.G. Hames, D.A. Olewine, F.H. Ramsey, and R. Meier. “Physical Activity, Catecholamines and Platelet Stickiness,” Myocardiology. Recent Advances in Cardiac Structure and Metabolism. E. Bajusz and G. Rona. eds.. pp. 742-752. University Park Press, Baltimore, 1972. 7.

Genton. E.. et.al. “Platelets. Thrombosis and Coronary Artery Disease.” Adv. Cardiol.. Vol. 9, 1973. p p . 29-39.

8. Born, G.V.R. “Quantitative Investigations into the Aggregation of Blood Platelets,” J. Physiol.. Vol. 162. 1962. pp. 67-68. 9. O’Brien. J.R. “Platelet Aggregation: Part 11. Some Results from a New Method of Study,’’ J. Clin. Pathol.. Vol. 15. 1962, pp. 452-455. 10. O’Brien, J.F.. J.B. Heywood, and J.A. Heady. “The Quantitation of Platelet Aggregation Induced by Four Compounds: A Study in Relation to Myocardial Infarction,” Thromb. Diath. Haemorrh.. Vol. 16, 1966. pp. 752767. 11.

Ginsburg, A.D., and R.H. Aster. “Platelet Function: Its Clinical Significance,” D . M.. Sept.. 1970, p. 17.

12. Gough. H.G. Cal$ornia Psychological Inventory. Manual. (Revised). Consulting Psychologists Press, Palo Alto, Calif., 1969. 13. Spielberger, C.L.. R. Gorsuch, and R. Lushene. State-Trait A n x i e t y Inventory. Preliminary Test Manual. Consulting Psychologists Press, Palo Alto, Calif., 1969. 14. Bendig. A.W. “The Development of a Short Form of the Manifest Anxiety Scale.”J. Consult. Ps.ychol.. Vol. 20, 1956, p. 384. 15. Buss, A.H. “A Follow-up Item Analysis of the Taylor Manifest Anxiety Scale,’’ J. Clin. Psychol.. Vol. 1 1 . 1955, pp. 409410. 16 Sieget, S. Nonparametric Statistics j o r the Behavioral Sciences, pp. 223-229. McGrawHill, New York, 1956. 17. Megargee. E.I. The California Psychological Inventory Handbook. Jossey-Bass, San Francisco, Calif., 1972. 18. Byrne, D.. D. Golightly. and 1. Sheffield. “The Repression-Sensitization Scale as a Measure of Adjustment: Relationship with the CP1,”J. Consult. Psychol,. Vol. 29, 1965, pp. 586-589.

December. 1975

Blood platelet aggregation and personality traits.

Changes in blood platelet aggregation may precipitate episodes of arterial occlusive diseases. Little is known, however, regarding the influence of ps...
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