Definitional, Epidemiological, and Assessment Issues 397depressed, ranging between 10.9 and 13.7, although there are
certainly subgroups (about 25% of females and 30% of
males) of patients falling in the normal range. Similarly,
scores on the STAI-state (current anxiety) range between
40.1 and 55.7, and scores on the STAI-trait (general anxiety)
range from 46.9 to 57.6, indicating mild to moderate anxiety.
Categorical Measures of Psychopathology
When we look at psychological distress categorically, IBS
patients also tend to show increased levels of disturbance.
Talley et al. (1992) reported that the majority of gastroen-
terology patients with IBS could receive at least one DSM-
III-Rdiagnosis. In addition, when compared with other GI
patients, non-GI patients, and healthy controls, more patients
with IBS reported current Axis I psychopathology (Talley
et al., 1993; Toner et al., 1990; Walker et al., 1990). Several
independent researchers have estimated that between 50%
and 100% of patients with IBS have diagnosable mental dis-
orders (Folks & Kinney, 1992).
Most often, psychiatric disturbances fall within the mood
disorder (prevalence of depression is estimated to be between
8% and 61%) and anxiety disorder spectrums (Lydiard,
Fosset, Marsh, & Ballenger, 1993; prevalence between 4%
and 60%). In one study of treatment-seeking IBS sufferers,
94% of the sample met lifetime criteria for one or more DSM-
III-RAxis I disorder, and 26% met the criteria currently
(Lydiard et al., 1993). However, the proportion of IBS sam-
ples with no Axis I diagnosis is variable, ranging from only
6% (Lydiard, 1992; E. A. Walker et al., 1990) to 66%
(Blewett et al., 1996; Walker et al., 1990). We have noted in
our own research that about 44% of our samples have been
free of Axis I psychopathology (Blanchard, Scharff, Schwarz,
Suls, & Barlow, 1990). However, when we look at patients
with nonfunctional bowel problems, such as in”ammatory
bowel disease (a good comparison sample as it has similar
symptoms and ”are-ups), up to 87% of patients are free of
Axis I psychopathology (Blanchard et al., 1990; Ford, Miller,
Eastwood, & Eastwood, 1987). Individuals with psychiatric
disorders often report more gastrointestinal distress than their
nonpsychiatric counterparts (Lydiard et al., 1994; Tollefson,
Luxenberg, Valentine, Dunsmore, & Tollefson, 1991).
Gender Differences in Psychological Distress
Recent research at our center (Blanchard, Keefer, Galovski,
Taylor, & Turner, 2001) identi“ed gender dif ferences in lev-
els of psychological distress among IBS treatment seekers,
although “ndings were far from conclusive. We examined
possible gender differences in psychological distress in a
sample of 341 treatment-seeking IBS patients (238 females,
83 males). Structured psychiatric interviews were available
on 250 participants. We found signi“cantly higher scores for
females than males on the BDI, STAI-Trait, and Scales 2 (de-
pression) and 3 (hysteria) of the MMPI. However, there were
no differences in percentage of the two samples meeting cri-
teria for one or more Axis I psychiatric disorders, with 65.6%
of the total sample meeting these criteria. Thus, we could
conclude from this study that gender differences in psycho-
logical distress appear to be a function of whether we use
dimensional or categorical measurement of psychological
distress. This issue clearly needs to be addressed in future re-
search, especially since many studies have used exclusively
female populations in both assessment (e.g., Whitehead,
Bosmajian, Zonderman, Costa, & Schuster, 1988) and treat-
ment (e.g., Toner et al., 1998) studies.
Another question that has not been adequately addressed
with respect to psychological distress in IBS populations
is that of whether IBS is a psychosomatic disorder or a
somatopsychic disorder. In other words, does psychiatric dis-
tress precede the diagnosis of IBS, or does IBS lead to psy-
chiatric distress? Blanchard et al. (1986) found reductions in
depression and anxiety among IBS patients whose GI symp-
toms were reduced as a result of treatment, whereas there
were no such reductions when GI symptoms were not im-
proved. Lydiard et al. (1993) attempted to answer this ques-
tion using a sample of 35 patients with moderate to severe
IBS. Approximately 40% of patients had a psychiatric disor-
der prior to the onset of IBS, and an additional 30% devel-
oped IBS and an Axis I disorder simultaneously (within the
same year). Walker and colleagues (E. A. Walker, Gelfand,
Gelfand, & Katon, 1996) also noted that 82% of their sample
experienced psychiatric symptoms prior to the diagnosis of
IBS. An answer to this question would provide useful insight
into the experience and treatment of the IBS patient.IBS Patient versus IBS NonpatientIt has been suggested that, at most, only 40% of those people
with IBS have seen a physician for their GI problems
(Drossman et al., 1993). What differentiates those who
seek treatment from those who do not? We have seen previ-
ously that IBS patients,people who seek help for their GI
symptoms, tend to be more psychologically distressed than
controls. However, there is some speculation that the same
does not hold true for IBS nonpatients,or people with IBS
who do not seek help for their symptoms. However, research
in this area is mixed.
Drossman and colleagues (1988) compared 72 IBS pa-
tients with 82 IBS nonpatients and 84 normal controls (no GI