for the Study of
Healthcare Organizations & Transactions
Somatization causes personal suffering, can have a detrimental effect on family relations, is a burden on the community, and is an important problem for public health. In psychosocial terms, somatization may reflect the definition of oneself as a sick person and thus result in the inappropriate use of health-care resources. A survey of 1242 college students found that 10.9% reported enough somatic complaints (at least 13 out of 35 symptoms) to cross the DSM-III-R threshold for Somatization Disorder. This group, which included 14.8% of women and 6.7% of men, also reported increased levels of health service utilization and of "abnormal" illness behavior. Reclassification of individuals according to the DSM-IV criterion, which requires the presentation of conversion symptoms and complaints in the sexual or reproductive spheres, resulted in the loss of some of the women and almost all of the men from this group. A factor analysis indicated that gastrointestinal, cardiopulmonary complaints, and pain constitute the core of somatization. Pseudoneurological "conversion", epileptiform symptoms, and problems in the genitourinary, sexual, and reproductive spheres are more peripheral. Because DSM-IV places heavy emphasis on the latter group of symptoms, the result may be that somatization, as a process, will be defined as a "female" tendency. Although Somatization Disorder, as a formal diagnosis has been studied in middle-aged women, a substantial group of young people, men as well as women, may engage in somatization as a means of self-presentation and social control. Further study of these young adults should provide insights into the mechanisms of somatization, including how individuals develop internal representations of illness, repertoires of illness behavior, and patterns of interaction with the healthcare system. Future studies should also explore effective early interventions that might be used with those young adults who inappropriately identify themselves as "sick" in order to conserve health-care resources.
MECHANISMS OF SOMATIZATION SOMATIZATION IN THE DSM RESEARCH QUESTIONS
METHOD RESULTS DISCUSSION
Individuals who exhibit multiple somatic symptoms (somatization)1 represent some of the most vexing mental health problems in general hospital and primary care practice (Martin, 1991). The essential feature of somatization is the presence of physical symptoms for which there are no demonstrable organic findings or known physiological mechanisms. Somatization causes personal suffering and can have a detrimental effect on a person's interactions with his/her family (Kellner, 1990). It is a burden on the community and an important matter of public health. It is a common cause of absenteeism and a large part of physicians' time and effort is spent investigating and treating individuals with multiple somatic symptoms (Kellner, 1990). An editorial described somatization as medicine's unsolved problem (Lipowski, 1987); on the other hand, it has been conceptualized as "the exciting area...between mind and body, and between health and disease" (Campo & Fritsch, 1994).
The per capita expenditure for the health care of this group of individuals is up to nine times the average per capita amount, which can be accounted for by this group's use of inpatient services (Smith, Monson, & Ray, 1986), e.g., this group of individuals spent an average of 7.6 days in the hospital per person per year, although most of this hospitalization was unnecessary (Maguire, Pentol, Allen, Tait, Brooke, & Sellwood, 1982). While the individuals who were studied had a variety of medical problems, there is a striking absence of significant life-threatening illness to correspond to the quantity of medical care utilized. Most were either self-limited illnesses or mild chronic processes, e.g., hypertension or degenerative arthritis. Nevertheless, when compared with "ill" individuals, the individuals exhibiting somatization tendencies perceived themselves as much more disabled. In fact, over half described themselves as "sickly" for most of their lives, and 83% had ceased work because of their health.
It has been difficult to assess the prevalence of Somatization Disorder. The NIMH Epidemiologic Catchment Area study (Robins, Helzer, Weissman, Orvaschel, Gruenberg, Burke, & Regier, 1984) reported the prevalence, for women, as .3% and .1% in the general population. Despite the relative rarity of this condition in the general population, these individuals are overrepresented in medical care settings. Othmer and DeSouza (1985) reported that 6% of women seen in their psychiatric outpatient clinic exhibited somatization tendencies. Several reports from in-hospital psychiatric consultation and liaison services put the prevalence at 2 to 8%.
Numerous investigators have studied the prevalence of somatization by examining visits to primary care physicians. For the most part, the proportion of individuals with somatic complaints for which no adequate physical cause was detected ranged from 10% to 30% (Kessel, 1960; Shepard, Cooper, & Brown, 1966), and in specialty clinics this proportion is usually higher (Kellner, 1986). In most individuals, somatic symptoms are more prevalent than emotional ones (Kellner & Sheffield, 1973). In a study of the Diagnostic and Statistical Manual (DSM-III) disorders in primary care, 26% of the individuals presented with somatization (Kellner, 1990). Prevalence studies show that the severity as well as the incidence of somatic symptoms form continua ranging from the common, mild, and transient to the chronic, extremely distressing, and incapacitating (Mayou, 1976).
However, examining the existence of somatization symptoms in the general population is important for understanding the underlying construct (Liu, Clark, & Eaton, 1997). Much of the DSM's focus has centered on clinical samples, but the use of diagnostic criteria in the general population, as well, is necessary in order to avoid artifacts and biases that may arise in clinical samples (Berkson, 1946; Cohen & Cohen, 1984).
As a formal diagnosis, Somatization Disorder has been commonly associated with middle aged women. As one example, the sample of individuals in the field trial of the Diagnostic Statistical Manual (DSM) IV criteria (Yutzy, Cloninger, Guze, Pribor, Martin, Kathol, Smith, & Strain, 1995) included only middle-aged women (range 40-52 years) who were predominantly white (66%) and who were known in a particular clinic, e.g., psychiatry, internal medicine, and/or family practice.
However, it should be noted that one criterion
for the formal diagnosis is a longstanding history of multiple, unexplained
medical complaints. A large body of evidence suggests that somatization, e.g.,
recurrent complaints of pain, is relatively common in children and adolescents
(see Campo & Fritsch, 1994 for a review of the literature). Indeed,
somatization may actually begin in adolescence (Livingston, Witt, & Smith,
1995) when the individual begins to develop a mental representation of illness
and its personal and social consequences. During this period, the individual
begins to incorporate "being sick" into his or her self-concept and
the sick role into his or her repertoire of social behaviors. Therefore, in
addition to studying the existence of multiple somatic symptom reporting in the
general population in order to avoid any bias that may occur due to the use of
clinical samples, it is necessary to study a younger population that includes
both men and women.
Individuals who somatize have been described throughout the history of medicine and various theories have been put forward in an attempt to explain somatization (see Kellner, 1990 for a review of mechanisms and comorbid conditions). The term somatization, coined by Steckel in 1943, was originally defined as a bodily disorder that arises as the expression of a deep-seated neurosis, especially of a "disease of the conscious" (Steckel, 1943, 580). This notion is clearly related to Freud's concept of conversion. To date, there is little agreement about the exact etiology of somatization. However, the major social and psychological perspectives are discussed below.
For example, physical complaints could reflect the somatic component, rather than the subjective feeling component, of the individual's negative emotional state (Kihlstrom, Mulvaney, Tobias, & Tobis, 1998). That is to say, an individual under stress might exhibit physical symptoms but we would expect medical tests to reveal an organic basis for the person's complaints -- tachycardia, for example, muscle tension, or excess gastric secretion. But this is precisely what is not found in somatization. In somatization, the person complains of gastrointestinal symptoms, for example, that cannot be objectively confirmed when a physical work-up is performed.
As another example, cybernetic self-regulation theories suggest that awareness of an internal state is a function of control processes that monitor the availability and urgency of internal compared to external information (Carver, 1979; Carver & Scheier, 1982, 1985, 1991). This cue competition theory posits that a varied external environment will reduce attention to internal information and so will decrease reporting of somatic sensations. Similarly, individual differences in public and private self-consciousness (Fenigstein, Scheier, & Buss, 1975) will determine the degree to which the person is aware of, and responds to, his or her own internal physical states. Therefore, those individuals who are most likely to report multiple unexplained symptoms are less likely to experience an external environment that focuses attention away from internal states. Again, however, the cue-competition theory assumes that individuals who exhibit somatic tendencies are attending to actual physical changes that should be detected by appropriate medical testing -- but that is not the case in somatization.
More likely, somatization tendencies arise from basic processes that involve self representation and self presentation (Kirmayer, 1984, 1986; Kleinman & Kleinman, 1985; Kihlstrom & Canter Kihlstrom, in press). Generally, individuals have two means for expressing emotional distress -- somatization and psychologization. In somatization, distress is referred to, and expressed by, the body: there is something wrong with the person's heart, stomach, etc. In psychologization (or psychosocialization), there is something wrong with the person's mind and social relations -- s/he is sad, family problems exist, and so forth. Thus, somatization contrasts to psychologization (Kirmayer, 1984). However, characterizing somatization as simply a function of the transfer of emotional distress into somatic complaints would be limiting. Other mechanisms that bias perception and shape expression may be crucial to the individual's experience (for a review, see Kirmayer, 1986). Somatization and psychologization perhaps can best be understood as contrasting methods of constructing illness meaning that assimilate emotional experience to either the bodily or the psycho-social realm.
The problem of abnormal illness behavior is one area in which the self would seem to be particularly relevant. As defined by Mechanic (1962), illness behavior refers to the way that symptoms are perceived, evaluated, and acted upon by the patient (McHugh & Valis, 1986). Therefore, illness behavior is neither normal nor abnormal. On the other hand, some illness behaviors are clearly less appropriate, or less adaptive, than others (Pilowsky & Spence, 1975). For example, even after having symptoms explained and a course of treatment suggested, the individual may remain highly concerned about the state of his or her health, may become annoyed at other people's reactions to his or her illness, or even envy those who are healthier. Or, the individual can retain a strong conviction that he or she is ill, even though the findings of physical exams, laboratory tests, and exploratory surgeries are negative.
Finally, another mechanism underlying somatization may involve the structure of the health care system. Medical diagnostics and procedures focus on the body and encourage somatic attributions of symptoms (Kirmayer, 1986). It is clear that in the United States, mental illnesses and disorders are still stigmatized to a relatively high degree. Therefore the benefits of the sick role tend to accrue to physical illnesses rather than psychiatric or psychosomatic illnesses (Blackwell, 1967). Individuals who exhibit somatic distress may be pursuing the most direct path toward reaping the benefits that may be derived from the sick role.
Individuals with somatization disorder pose a
serious challenge to those concerned with the provision of health care. Not only
are they high utilizers of health-care services, but their identification and
appropriate treatment requires the coordinated efforts of both health and
mental-health personnel. Thus, the identification of individuals who exhibit
multiple somatic complaints, or individuals at risk for developing somatization
disorder represent an important task for public health.
SOMATIZATION IN THE DSM
When the DSM was first introduced in 1952, psychiatric syndromes were divided into three broad categories. Somatization Disorder was subsumed somewhere in the category "Disorders of psychogenic origin" (Kihlstrom, 1994). In 1968, with the introduction of DSM-II, Somatization Disorder most closely fell within the rubric of "Hypochondriacal Neurosis" (Kihlstrom, 1994). When it was introduced in 1980, DSM-III seemed to represent a paradigm shift for psychiatry (Tucker, 1998) in that it explicitly defined diagnostic criteria. With respect to the formal diagnosis of Somatization Disorder, DSM-III and later DSM-III-R (1987) both listed groups of symptoms or complaints that covered pseudoneurological, gastrointestinal, female reproductive, psychosexual, pain , and cardiopulmonary symptoms. For women, DSM-III required that 14 symptoms out of 37 be endorsed (12 for men) for a formal diagnosis. With the advent of DSM-III-R, 13 of 35 symptoms were required for the diagnosis and no distinction between men and women was made.
For a variety of reasons, neither clinicians nor
academics were satisfied with the criteria as outlined in DSM III and III-R (Yutzy,
et al., 1995). Therefore, after a reanalysis of 500 psychiatric outpatients a
modified set of criteria was proposed (Cloninger & Yutzy, 1993) and
incorporated into DSM-IV in 1994. In this revised version, the following
complaints must be reported in order to pass the threshold for the formal
diagnosis of Somatization Disorder: four pain, two gastrointestinal, one sexual
or reproductive, and one pseudoneurological.
The studies reported in this paper were designed to answer the following questions:
During the Spring, 1993, a study of multiple somatic symptoms in young adults was conducted utilizing a representative sample of students (N=683; 51% female) who were enrolled in a large public university. The mean age of the sample was 19.5 years (SD = 2.62). A total of 623 of the participants (91.2% of the sample) provided information on their ethnic heritage. Based on these reports, the racial and ethnic composition of the sample was representative of the population from which it was drawn, as reflected in student body statistics published by the university: White (population, 73.5%; sample, 77.4%); Hispanic (12.7% vs. 11.4%); Asian-Americans (4.6% vs. 6.6%); African American (2.4% vs. 2.4%); American Indian (1.8% vs. 1.1%); and Other (5.0% vs. 1.1%).2 Individuals were also asked to provide information on their mothers' and fathers' occupational and educational levels on 8- and 7-point scales, respectively; 620 participants (90.8% of the total sample) provided complete information on these variables.
A self-report questionnaire, Medical Problems
and Complaints (MPC), was constructed based on the criteria for Somatization
Disorder listed in DSM-III-R (American Psychiatric Association, 1987), and the
Somatization Disorder section of the Structured Clinical Interview for DSM-III-R
(SCID; Spitzer, Williams, Gibbon, & First, 1990). MPC listed the 35 critical
symptoms from DSM-III-R, representing problems in the gastrointestinal,
cardiopulmonary, genitourinary, sexual, and female reproductive spheres,
conversion or pseudoneurological symptoms, and pain. Individuals were asked to
indicate on a 3-point scale (1 = definitely no; 2 = uncertain; 3 = definitely
yes) the degree to which they had been "bothered" by each symptom in
the past. Appendix 1 shows the items of the MPC.
Although the purpose of this research was to identify young adults in a
generally healthy population who report a large number of somatic complaints,
and not to assign a formal diagnosis of Somatization Disorder, the DSM-III-R and
DSM-IV diagnostic criteria were also considered in the analysis of the MPC data
in an attempt to compare the results with others that are reported in the
A second study was conducted in the Spring, 1994
(N=559; 52.6% female) at the same host university as Study 1, employing the same
sampling and survey procedures. The mean age of the sample was 19.9 years (SD
= 3.97). As in Study 1, the racial composition of the sample closely paralleled
the composition of the student body of the host university and that of the
sample employed in Study 1: White (72.3%); Hispanic (13%); Asian-Americans
(7.8%); African American (2%); American Indian (2.2%); and, Other (2.7%). In
addition to the MPC, participants in this study completed a 14-item
questionnaire developed by Pilowsky and Spence (1975) to measure hypochondriasis
and other aspects of abnormal illness behavior. They were also asked to report
their utilization of health care services during the previous 12-month period.
A total of 683 individuals (335 men, 348 women) provided complete data on the somatization questionnaire. Table 1 shows the proportion of participants (male, female, and total) who gave each symptom the highest possible rating of 3. The most frequently endorsed symptoms were in the gastrointestinal and cardiopulmonary domains, and pain in various spheres.
Distribution of somatic complaints. The average number of symptoms endorsed by participants was 5.91 (SD = 5.17), with a range from 0 to 27, and a radically skewed distribution (Figure 1). The reliability coefficient of the total MPC score was .90 (Carmine's theta).
There was a significant gender difference in total somatization scores: males, M = 4.58, SD = 4.97; females, M = 7.19, SD = 5.04; t(681) = 6.82, p < .001. However, four 4 of the MPC items (#s 32-35) can only be endorsed by women. Eliminating these items from the analysis significantly reduced the women's mean score to 6.13 (SD = 4.55), t(347) = 18.71, p < .001.Nevertheless, a statistically significant gender difference remained even after excluding these four "female only" symptoms: t(681) = 4.26, p < .001.
An one-way between-group analysis of variance (ANOVA) revealed no differences in MPC score among the various racial and ethic groups (F < 1.0). There were also no differences according to socioeconomic status, as indicated by separate one-way between-group ANOVAS with father's and mother's occupation and level of education serving as independent variables (all Fs < 2, all ps > .20).
Structure of somatization. A principal components analysis yielded nine factors with eigenvalues greater than 1.0, accounting for 54.2% of the variance in the data space; the unrotated first factor accounted for 40.5% of the factor space. Table 1 shows the loading of each MPC item on the unrotated first factor: loadings are provided for the entire sample, and for males and females analyzed separately. Table 2 shows the results when these nine factors were subjected to orthogonal (varimax) rotation. Factor 1 consisted primarily of gastrointestinal complaints, pain, and throat problems; Factor 2, cardiopulmonary symptoms and pain in the extremities; Factor 3, menstrual complaints; Factor 4, pseudoneurological "conversion" symptoms affecting hearing and vision; Factor 5, amnesia and pseudoneurological "conversion" symptoms affecting motor function; Factor 6, sexual problems; Factor 7, epileptiform symptoms; Factor 8, genitourinary problems and disinterest in sex; and Factor 9, vomiting during pregnancy. Note that Factors 3 and 9 were defined by items that could be endorsed only by women. Further, because many individuals in this sample may not have been sexually active, Factors 6 and 8 are somewhat ambiguous.
Because the MPC included four gender-specific items, the principal components analysis was repeated for males (excluding these items) and females (including all items) taken separately. As might have been expected, by virtue of the elimination of items comprising two of the nine factors obtained in the combined analysis, the male data yielded seven factors. However, the structure of the female data was more complex than the combined solution, entailing 12 factors. In the female subsample, the additional factors were generated by splitting Factor 2 into two separate factors representing pain and cardiopulmonary symptoms, respectively; and Factor 4 into three factors representing various pseudoneurological complaints into various spheres.
Comparison of diagnostic criteria. In this sample, a total of 89 individuals (13.0%) met the DSM-III-R criterion for Somatization Disorder, endorsing 13 or more of the 35 symptoms listed on the questionnaire. This group included 34 men (10.1% of all men), and 55 women (15.8% of all women). However, only 64 individuals (9.4%) met the DSM-IV criterion: these included a somewhat different group of 55 women (15.8% of all women) but only 9 men (2.7% of men). Put another way, only 46 of the 89 participants (51.7%; 6 men and 40 women) who met the DSM-III-R criterion also met the DSM-IV criterion; the remaining 43 individuals (28 men, 15 women) met the DSM-IIIR criterion, but not the DSM-IV criterion; finally, 18 individuals (3 men and 15 women) met the DSM-IV criterion but failed to meet the DSM-III-R criterion as well. Thus, the DSM-IV criterion missed almost all those males who were classified as at risk for Somatization Disorder according to DSM-III-R, and many of the women as well (Table 3A).
Those individuals who were identified as being
at-risk by one criterion, but not the other, had highly similar symptom
profiles. Analysis by t tests showed that, compared to the 43
participants who met only the DSM-III-R criterion, the 46 individuals who met
both criteria were significantly more likely (p < .05) to endorse the
following items: sex unimportant (MPC Item #29, 30.4% vs. 7.0%), painful
menstruation (#32; 67.4% vs. 14.0%)), irregular menstruation (#33; 63.0% vs.
16.3%), and excessive menstrual bleeding (#34; 54.3% vs. 14.0%). Individuals who
met only the DSM-III-R criterion, but not the DSM-IV criterion as well, were
significantly more likely to endorse only one item, pain in arms and legs (#7;
90.7% vs. 73.9%).
A total of 559 individuals (265 men, 294 women) completed the full somatization questionnaire. Table 4 shows the proportion of participants (male, female, and total) giving each symptom a rating of 3. As in Study 1, the most frequently endorsed symptoms were in the gastrointestinal and cardiopulmonary domains, and pain.
Distribution of somatic complaints. The average number of symptoms endorsed by individuals in Study 2 was slightly lower than in Study 1: 4.35 (SD = 4.65), with a range from 0 to 26; again, the distribution of scores was radically skewed (Figure 1). The reliability coefficient of the MPC questionnaire was again .90 (Carmine's theta). An analysis using a t-test yielded a significant gender difference in total somatization scores: males, M = 2.67, SD = 3.46; females, M = 5.93, SD = 5.05; t(557) = 8.79, p < .001. Eliminating the four gender-specific items from the analysis significantly reduced the women's mean score to 5.11 (SD = 4.54), t(293) = 14.31, p < .001, but the gender difference remained significant: t(557) = 7.08, p < .001. As in Study, ANOVA revealed no significant differences in MPC according to race and ethnicity (F < 1), father's occupation (F < 1), or mother's occupation (F < 2, p > .40). In contrast to Study 1, however, ANOVA did reveal significant effects of mother's educational level, F(6, 539) = 2.57, p < .05; there was also a strong trend for father's educational level, F(6, 531) = 1.96, p < .07. In both cases, individuals whose parent had completed college, but not graduate school, endorsed the highest number of symptoms on the MPC.3
Structure of somatic complaints. Principal-components analyses with orthogonal (varimax) rotation of the MPC items, performed on the entire sample and repeated for male and female subsamples taken separately, yielded results closely resembling those obtained in Study 1. Table 4 shows, for all participants and for males and females analyzed separately, the loadings of each MPC item on the first unrotated factor. The factor analyses of Sample 2 are not further described further in this paper, out of considerations of space, but they are detailed in an expanded version of this report available from the first author.
Comparison of diagnostic criteria. In this sample, a total of 46 individuals (8.2%) met the DSM-III-R criterion for Somatization Disorder, endorsing 13 or more of the 35 symptoms listed on the questionnaire. This group included 6 men (2.3% of all men), and 40 women (13.6% of all women). However, only 39 individuals (7.0%) met the DSM-IV criterion: these included 36 women (12.2% of all women) but only 3 men (1.1%). As in Study 1, only 30 of the 46 participants (65.2%; 1 man and 29 women) meeting the DSM-III-R criterion also met the DSM-IV criterion; 16 (5 men and 11 women) met only the DSM-III-R criterion; 9 individuals (2 men and 7 women) met the DSM-IV criterion but failed to meet the DSM-III-R criterion as well. Thus, again, the DSM-IV criterion missed almost all those males who were classified as being at-risk for Somatization Disorder according to DSM-III-R, and some of the women as well (Table 3B).
As in Study 1, participants who were identified as being at-risk by one criterion, but not the other, had highly similar symptom profiles. Analysis by t tests showed that, compared to the 16 individuals who met only the DSM-III-R criterion, the 30 participants who met both criteria were significantly more likely (p < .05) to endorse the following items: vomiting (MPC #1; 83.3% vs. 56.3%); abdominal pain (#2; 86.7% vs. 50.0%); irregular menstruation (#33; 76.7% vs. 25.0%); and excessive menstrual bleeding (#34; 63.3% vs. 12.5%). Individuals who met only the DSM-III-R criterion, but not the DSM-IV criterion as well, were significantly more likely to endorse only one item, pain when urinating (#10; 31.3% vs. 6.7%).
consultations and abnormal illness behavior. Individuals who met
the DSM-III-R criterion for Somatization Disorder reported a greater number of
medical consultations (M = 5.59, SD = 6.82) than the remaining
participants who did not meet this criterion (M = 2.35, SD =
2.90), t(554) = 6.20, p < .001).4
They also reported significantly higher levels of "abnormal" illness
behavior (M = 6.46, SD = 3.35, vs. M = 4.21, SD =
2.18) on the 14-item illness behavior scale,5t(447)
= 5.72, p < .001. Significant differences were also found when the
individuals were reclassified according to the DSM-IV criterion: consultations, t(554)
= 5.54, P < .001; illness behavior, t(447) = 5.56, p
< .001. Importantly, individuals who were identified as being at-risk by one
criterion, but not the other, did not differ significantly (both p >
.15) in terms of either number of medical consultations or in levels of abnormal
Somatization in young adults. Studies of somatization in children and adolescents have been problematic because there has been little consistency in the use of instruments and methodology; therefore, the studies are difficult to compare. Studies of somatization in the pediatric population have focused on particular physical symptoms and have not used psychiatric diagnostic criteria. Moreover, the studies did not address whether the reported symptoms resulted in functional impairment and/or an increased use of health care services (Campo & Fritsch, 1994).
The present research suggests that individuals as young as 19 years old exhibit multiple somatic complaints. Across the two samples totaling 1242 college students, approximately 135 (10.9%) of those surveyed reported enough somatic complaints to cross the DSM-III-R threshold of 13 symptoms (out of a possible 35). Most of the complaints were either reports of "pain" or of gastrointestinal disturbances In Study 2, these students also reported a relatively high number of visits to medical personnel in the past year, and a pattern of response to their symptoms characteristic of "abnormal" illness behavior. The implication is that these individuals may have already developed a mental representation of themselves as "sick" by the time they entered college.
As noted above, the intent of these studies was not to diagnose Somatization Disorder; rather, the focus was to assess whether multiple somatic complaints could be detected in a relatively young and presumably healthy, well-functioning population: college students. Studies whose intent was to derive a formal diagnosis of Somatization Disorder have been largely based on clinical samples and on data gathered through the use of a structured interview format, e.g., the Structured Clinical Interview for DSM-III-R (SCID) or the structured Diagnostic Interview Schedule (Robins, Helzer, Croughan, & Ratcliff, 1981). As measurement methods, both the interview and the questionnaire have advantages and disadvantages (see Stone, 1978 for a concise review of these methods) and serve particular purposes. Therefore, interviews per se should not be viewed as a gold standard.
It should be noted that in this study, utilization data were gathered through self-report. In future studies, health care utilization should be examined by some other means in order to verify the self-report data because, in some cases, the symptoms reported by the students may be attributable to some actual medical problem. However, many of the students who reported a large number of symptoms did not receive medical diagnoses sufficient to explain them. If these individuals appeared in a medical clinic presenting such a pattern of complaints, they might raise concerns about somatization tendencies, but might, nevertheless, continue to receive unnecessary or ineffective treatment. The finding of higher utilization by individuals who reported a high level of somatic complaints suggests that these individuals should be examined further, even if ultimately they do not qualify for a formal diagnosis of Somatization Disorder.
Gender Issues. Current diagnostic criteria do not limit Somatization Disorder to one gender. However, as noted above, in the past somatization has been studied almost exclusively in women. In fact, the present research yielded more evidence of somatization in women than in men. This was true even when gender-specific symptoms (e.g., dysmenorrhea) that would inflate the gender difference were eliminated from consideration. At the same time, these studies indicated that men as well as women displayed patterns of symptomatic complaints indicative of somatization. In the two studies, 40 of 600 men (6.67%) compared to 95 of 642 women (14.8%) crossed the DSM-III-R threshold. Thus, future attempts, in either clinical samples or population-based samples, to identify somatization and/or to intervene in its course should include men as well as women.
Structure of Somatization. Research employing diagnostic interviews in an adult population has revealed that somatic complaints are factorially complex (Liu et al, 1997; Swartz, Blazer, Woodbury, George, & Landerman, 1986), and these findings were confirmed with the MPC questionnaire administered to this sample of young adults. Although the MPC questionnaire total scores possessed highly satisfactory levels of reliability (internal consistency), it is also clear that somatic complaints are multidimensional in nature and that the internal structure of somatic complaints differs somewhat for men and for women. The responses from both men and women demonstrate a strong primary factor consisting of gastrointestinal complaints, pain, and throat problems. A second factor consisted of cardiopulmonary symptoms and pain in the extremities; this factor was confirmed in the male subsample, while the two domains were split into separate factors in women. These four symptom categories -- gastrointestinal and cardiopulmonary complaints, throat problems, and pain -- also loaded strongly on the unrotated first factor, and may be considered to comprise the core of somatization. Interestingly, these core complaints resemble the kinds of symptoms that would be seen by primary-care physicians.
By contrast, pseudoneurological "conversion" and "dissociative" symptoms lined up on different factors in the rotated solution, as did epileptiform symptoms and problems in the genitourinary, sexual, and reproductive spheres; these complaints also showed relatively low loadings on the unrotated first factor. This pattern of findings indicates that these particular symptom categories do not belong in the domain of somatization. Interestingly, Liu et al. (1997) drew the same conclusion from their factor-analytic study of data collected during the Epidemiological Catchment Area (ECA) study. On theoretical grounds, Kihlstrom (1992, 1994) has argued that "conversion" symptoms of blindness, deafness, tactile anesthesia, paralysis, and the like are dissociative in nature, involving disruptions in the monitoring and/or controlling functions of consciousness, and are inappropriately included in the Somatoform category. This proposal receives some empirical support from the present data, as well as that of Liu et al. (1997). On similar empirical grounds, it would appear that problems in the genitourinary, sexual, and reproductive spheres should likewise be excluded. In the final analysis, then, somatization, and Somatoform Disorder in general, is best represented by the kind of complaints that would be made to, and treated by, a primary-care physician or specialist in internal medicine.
Mechanisms of Somatization. What has not been extensively documented in the literature and what should be addressed in future studies are the factors that may contribute to the development of a "self-as-sick" concept and to the incorporation of the sick role into the individual's repertoire of social behaviors. In one study that was conducted in Finland, Poikolainen, Kanerva, and Lonnqvist (1995) found that among adolescent females, somatic symptoms were associated positively with serious illness or injury in the family, with an increased number of arguments between parents, and with the termination of friendships. For male adolescents, symptoms were associated with an increased absence of a parent from the home and trouble with siblings. Among all of the adolescents studied, increased symptoms were associated with failing examinations in school. However, the investigators caution that follow-up studies are needed to clarify the predictive value of these antecedents.
In addition to these antecedents, Livingston, Witt, and Smith (1995) found that factors within the family may contribute to somatization in a child. They found that parental diagnoses that tested as predictors included parental somatization, antisocial personality, major depression, any alcohol or drug use disorder, and any anxiety disorder. Similar to the adults who somatize, Livingston et al., (1995) found that children who somatize utilized more health care services, e.g., emergency use, exhibited suicidal behavior, and tended to miss school. However, much more research into these familial variables should be conducted.
Changes to the DSM. This research also demonstrates that the organization and enumeration of diagnostic criteria may result not only in a fundamental change to the underlying construct but to its differential application. In this series of studies, when DSM-IV and DSM-III-R criteria were applied to the same sample of young adults, different results emerged. In general, the DSM-IV criterion identified not only different individuals than did DSM-III-R criterion, it identified fewer individuals. In particular, fewer males were identified by the DSM-IV criterion. This is perhaps accounted for by the requirement that at least one sexual or reproductive symptom, other than pain, be reported.
It is possible that women, particularly young women, are more comfortable reporting symptoms such as excessive menstrual bleeding or irregular menses than men are in reporting symptoms such as sexual indifference or erectile or ejaculatory dysfunction. It may be that these questions are tapping the social desirability of endorsing sensitive questions rather than the presence or absence of the actual symptom. If the real issue is one of responding to sensitive questions (for males vs. females) and if endorsement of sensitive questions is required for a formal psychiatric diagnosis, then the danger is that Somatization Disorder will be detected only in females. Further methodological research is required to determine if the different levels of social desirability that are attached to "sensitive" questions can account for some of the differences between young men and young women with respect to symptom reporting.
The transition from high school to college and
adulthood is a critical developmental milestone. At this age, many individuals
leave home for the first time and begin to establish their own habits and
lifestyles, including patterns of interaction with the health care system.
Attitudes toward illness and medical care that exist at this point may last a
lifetime. Future studies should examine underlying attitudes toward illness
among young adults, identify young adults who report multiple somatic symptoms,
assess their functional status and possible associated psychological disorders,
and examine, prospectively, health care utilization patterns. In the future, the
research effort should focus less on reorganizing and symptom counting and more
on identifying the underlying mechanisms that lead to multiple somatic symptom
This research was supported by Grant #MH-35856
from the National Institute of Mental Health. These results were first reported
in a paper presented by L.C. Kihlstrom and K. F. Marsh at the annual meeting of
the American Public Health Association in Washington, D.C. (1994) and in a paper
presented by L.C. Kihlstrom, K.F. Marsh & J.F. Kihlstrom at the annual
meeting of the Association for Health Services Research in Washington, D.C.
1The use of somatization and Somatization Disorder can be confusing. In this paper, the term somatization will be used to mean reports of multiple somatic complaints. When the formal diagnostic category is referred to, the phrase Somatization Disorder will be used. Return to text
2By way of comparison, in the 1990 census, the racial and ethnic distribution of the state in which the university was located was: American Indian, 5.6%; Asian, 1.5%; African-American, 3.0%; White, 80.8%; Hispanic, 18.8%; Other, 9.1%.Return to text
3As in Study 1, not all participants reported the relevant data, but each ANOVA was based on a minimum N of 504 individuals.Return to text
4Only 556 individuals provided this information, including all 46 participants who met the DSM-III-R criterion for Somatization Disorder.Return to text
5Only 449 individuals (37 meeting the DSM-III-R criterion for Somatization Disorder, and 412 others) completed the brief Illness Behavior Scale. The reliability of the scale was .78 (Carmine's theta).Return to text
References (click on to see references)
Lucy Canter Kihlstrom, PhD
Institute of Personality and Social Research
University of California, Berkeley
Kenneth F. Marsh, PhD
Counseling & Psychological Services
Campus Health Service
University of Arizona, Tucson
John F. Kihlstrom, PhD
Department of Psychology
University of California, Berkeley
Copyright © 2000 Institute for the Study of Healthcare Organizations & Transactions
Last modified: 03.26.2004 11:03 PM