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Role of distress in delusion formation
MANON HANSSEN, LYDIA KRABBENDAM, RON de GRAAF, WILMA VOLLEBERGH and JIM van OS
The British Journal of Psychiatry 2005 187: 55-58
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B R I T I S H J O U R N A L O F P S YC H I AT RY ( 2 0 0 5 ) , 1 8 7 ( s u p p l . 4 8 ) , s 5 5 ^ s 5 8
Role of distress in delusion formation* 18–64 years participated. Trained lay inter-
viewers in all three measurements applied
the Composite International Diagnostic
GRAAF,
MANON HANSSEN, LYDIA KRABBENDAM, RON DE GR A AF,
Interview (CIDI; Smeets & Dingemans,
WILMA VOLLEBERGH and JIM VAN OS
1993). The CIDI has 17 psychosis items
(13 delusions, 4 hallucinations) with six
possible ratings for each psychosis item:
(1) no psychotic experience; (2) no clini-
cally relevant psychotic experience; the
individual is not experiencing distress and
is not seeking help; (3) and (4) psychotic
experience is the result of drug misuse or
Background Contemporary cognitive Hallucinations and delusions tend to co- somatic disease; (5) true psychiatric symp-
psychological theories suggestthat occur both in clinical and in non-clinical tom; individual experiences distress and/or
samples (Liddle & Barnes, 1990; Johnstone seeks help; (6) what appears to be a true
distress plays a mediating role in delusion
al,
& Frith, 1996; van Os et al, 2000). One psychotic symptom may not be a real symp-
formation. possible explanation for this association tom because there appears to be some plau-
may be that the experience of hallucina- sible explanation for it, i.e. it may actually
Aims To study the amplifying role of
tions gives rise to secondary delusional exist.
exist.
distress from earlyperceptualintrusions to Clerambault,
interpretations (De Clerambault, 1942;
´ At baseline, the lay interviewers en-
delusion formation. Maher, 1988). Little is known, however, quired about lifetime presence of symptoms
about the factors that mediate the transi- and at the two follow-up measurements the
Method A general population sample tion from hallucinatory experience to delu- period between the measurements was
of 7076 individuals was interviewed with sional interpretation. Recent psychological assessed. For the current analysis, ratings
the Composite International Diagnostic hypotheses on delusion formation of 2 and 5 on the four hallucination items
emphasise the role of attributional style, at baseline, both indicative of the presence
Interview (CIDI) in1996 (baseline),1997
distress and worry in the aetiology and of a psychotic experience in the absence of
(T1) and1999 (T2). At T2, clinicians also maintenance of delusions (Garety et al, al, doubt or secondary cause but crucially dif-
scored the Brief Psychiatric Rating Scale 2001). Thus, the experience of voices or ferent in terms of subjective distress and
(BPRS) item‘unusual thought content’. visions may lead to full-blown delusional help-seeking behaviour, were included in
Analyses compared hallucinatory ideation, when it is attributed to an the analyses. The distinction between the
external source or when it is given personal ratings of 2 and 5 was validated in a
experiences with and without subjective
significance. al,
previous study (van Os et al, 2001). The
distress at baseline for risk of delusion In an earlier study, for example, it was four hallucination items encompassed all
formation at follow-up. reported that delusion formation in possible hallucinatory modalities.
adolescents hearing voices was mediated At baseline and T2, attempts were
Results Individuals experiencing by, among other factors, attributions of made to clinically validate the lay inter-
hallucinations with distress, compared externality, perceived power over the viewer-administered CIDI interview. Each
with those without distress had a fourfold person and emotional appraisals (Escher time, when at baseline (possible) psychotic
al,
et al, 2002). We wished to extend these symptoms (CIDI rating of 5 or 6) were de-
increased risk of subsequent delusion
results to a large general population sample tected in the NEMESIS study, a psychiatric
formation. that had no previous evidence of delusional clinician conducted clinical re-interviews
ideation. It was hypothesised that people over the telephone by using the Structured
Conclusions This finding corroborates
experiencing hallucinations with distress Clinical Interview for DSM–III–R (SCID;
the hypothesis that distress associated at baseline, compared with those without, al,
Spitzer et al, 1992). If a clinician did not
with earlyperceptualintrusions serves as a would show a greater risk of developing agree with the psychosis rating of the
catalyst in the development of delusions. delusions over the follow-up period. trained lay interviewer, the psychosis rating
was changed to the rating of the clinician.
Declaration of interest None. All DSM–III–R diagnoses in the NEMESIS
Funding detailed in Acknowledgements. METHOD study are based on these corrected ratings.
At baseline, 47.2% of the eligible individ-
Procedure, instruments uals were actually interviewed. The prob-
and sample ability of a selection bias was assessed in
The Netherlands Mental Health Survey and a previous study and deemed unlikely
Incidence Study (NEMESIS study) is a large al,
(Hanssen et al, 2003). At T2, all individuals
general population study with three with a rating of 2, 5 or 6 on any CIDI
measurement points (hereafter: baseline, psychosis item were administered a clinical
*Paper presented at theThird International Early T1 and T2) in 1996, 1997 and 1999. At re-interview over the telephone by an
Psychosis Conference,Copenhagen,Denmark, the three measurement points, respectively experienced clinician. The proportion of
September 2002. 7076, 5618 and 4848 individuals aged eligible individuals who were successfully
s55
HANS S EN E T AL
re-interviewed was 74.4%. At T2, the compared using the Wald test. In order to without distress were reported by 79
clinician also scored the ‘unusual thought exclude misclassification at the lower end (1.9%), 26 (0.6%), 34 (0.8%) and 60
content’ item of the Brief Psychiatric Rating of the BPRS scoring range of the unusual (1.4%) individuals, respectively. Visual,
Scale (BPRS; Lukoff et al, 1986). The BPRS
al, thought content item, analyses were re- auditory, olfactory and tactile hallucina-
symptom items are rated on a seven-point peated with a more stringent definition of tions accompanied by distress were present
scale on the basis of frequency of the the BPRS ‘unusual thought content’ item in 19 (0.5%), 8 (0.2%), 5 (0.1%) and 8
symptom and functional impairment. as a dependent variable, i.e. a score 42. (0.2%), respectively. In the group of 161
Ratings 2–3 represent a non-pathological Finally, in an attempt to clinically validate individuals who reported hallucinatory
form of the symptoms and ratings 4–7 any findings, analyses were repeated using experiences without distress, the propor-
represent a pathological form (Lukoff et the clinical definition of delusions, namely tions of visual, auditory, olfactory and
al, 1986). For a more detailed description
al, a score 43 on the BPRS item ‘unusual tactile hallucinations were 49.1% (79/
of the NEMESIS study see Bijl et al thought content’, which is indicative of 161), 16.2% (26/161), 21.1% (34/161) and
(1998) and van Os et al (2001). the level of pathology in terms of functional 37.3% (60/161), respectively. In the dis-
al,
impairment (Lukoff et al, 1986). (n 32)
tress group (n¼32) these proportions were
59.4% (19/32), 25.0% (8/32), 15.6%
Analyses: the development Sensitivity analyses (5/32) and 25.0% (8/32), respectively.
of delusions Thirty-seven individuals in the risk set
Sensitivity analyses were conducted to
The study sample at T2 was restricted to examine whether differential attrition in (males: 35%) had developed delusions
individuals who did not report delusions the sample as a whole (7076 at baseline, (BPRS4
(BPRS41) at T2, 16 of these 37 (males:
at baseline and again at T1 (i.e. had no 4848 at T2) could have biased the findings. 56%) had developed delusions with a BPRS
ratings of 2 or 5 on any of the CIDI delu- This was done by multiple imputation of score 42, and 7 (males: 71%) of these 16
sion items at baseline and T1) in order to missing values of delusional ideation at T2 had developed clinical delusions according
skew the sample towards people with true (n¼1962 missing, 31.4%) using the
1962 (BPRS4
to the BPRS definition (BPRS43).
incident delusions at T2 (original sample HOTDECK command in Stata. The
4848;
at T2: n¼4848; sample restricted to those HOTDECK procedure is used several times Distress and delusion formation
without delusions at baseline and T1, and within a multiple imputation sequence as The risk for delusion formation at T2 was
non-missing data on the delusion variable missing data are imputed stochastically five times greater in the individuals who
at T2, hereafter referred to as ‘risk set’: rather than deterministically. A total of at baseline were distressed by their halluci-
4236;
n¼4236; risk set and non-missing covari- 1000 imputation sequences were run, yield- nations (6 out of 32 persons reporting
4181).
ates: n¼4181). ing 1000 data-sets in which the regression hallucinations with distress developed delu-
All analyses were carried out with Stata coefficients were estimated within the (BPRS4 OR 25.0,
sions (BPRS41: OR¼25.0, 95% CI 9.3–
version 7 Special Edition (StataCorp, HOTDECK procedure. Imputation of miss- 67.8) than in the individuals who reported
2001). Logistic regression analysis was per- ing values was stratified by known risk fac- hallucinations without distress (7 out of
formed with the BPRS ‘unusual thought al,
tors of psychosis (van Os et al, 2000, 2001, 161 persons reporting hallucinations with-
content’ item measured at T2 as a depen- al,
2002; Krabbendam et al, 2002; Janssen et (BPRS4
out distress developed delusions (BPRS41:
dent variable (score 1 rated absent and al,
al, 2003), namely age, gender, urbanicity, OR 4.9,
OR¼4.9, 95% CI 2.0–11.9) (Table 1). This
score 41 rated present) and the baseline ethnic group, neuroticism, experience of difference was statistically significant
CIDI ratings on hallucinations with and discrimination, experience of abuse before (w2¼5.2, d.f.¼1, P¼0.02). After adjustment
5.2, d.f. 1, 0.02).
without distress (entered as two dummy the age of 16 years, educational level, for the covariates, the difference remained
variables) as independent variables. To unemployment and single marital status. robust (w2¼3.8, d.f.¼1, P¼0.05) (Table 1).
(w 3.8, d.f. 1, 0.05)
account for possible confounding variables, The HOTDECK procedure replaces miss- Results were similar using the more
we controlled for the following a priori ing values in the relevant variables by (BPRS4
stringent definition of delusions (BPRS42),
chosen covariates, guided by previous find- values randomly sampled from complete with again a highly significant difference in
al,
ings in this sample (van Os et al, 2000, lines in the same stratum. Individuals who effect size (w2¼8.7, d.f.¼1, P¼0.003)
(w 8.7, d.f. 1, 0.003)
2001, 2002; Krabbendam et al, 2002;al, had delusions at baseline and at T1 were (Table 1), also after adjustment of covari-
al,
Janssen et al, 2003): age (5 categories), again excluded from these analyses ates. Similar results were apparent for the
gender, urbanicity (3 levels), ethnic group 831).
(n¼831). clinical definition of delusions: no individ-
(0: person and both parents born in the
uals with hallucinations without distress
Netherlands and 1: other), neuroticism (Or- RESULTS developed clinically relevant delusional
mel, 1980), experience of discrimination (a
Data ideation, whereas the risk was very high
6-item questionnaire measuring experience
in those whose hallucinatory experiences
of discrimination regarding the colour of At baseline and limited to the risk set
were accompanied by distress (Table 1).
skin or ethnicity, gender, age, appearance, 4236),
(n¼4236), 161 individuals (males: 34.8%)
handicap and sexual orientation), experi- reported lifetime occurrence of hallucina-
ence of abuse before the age of 16 years tions without distress, whereas 32 (males: Sensitivity analyses
(a 4-item questionnaire), educational level 21.9%) reported hallucinations with dis- Using 1000 imputation sequences in which
(4 levels), unemployment and single marital tress. Five subjects reported both types of missing values of the outcome of delusions
status. The effect sizes of baseline halluci- hallucinations. at T2 were imputed stochastically, the
nations with and without distress on risk (n 4236),
In the risk set (n¼4236), visual, audi- estimated effect size for baseline hallucina-
for delusion formation at T2 were tory, olfactory and tactile hallucinations (OR 18.3,
tions with distress was (OR¼18.3, 95%
s56
OR
R OL E OF D I S T R E S S IN D E LU S I ON F OR M AT I ON
Table 1 Comparison between hallucinations with and without distress regarding the formation of delusions also be relevant in this regard. Hemsley’s
3 years later cognitive model hypothesises that the
problem in schizophrenia encompasses the
Covariates Baseline Baseline w2 d.f. P inability to integrate the moment-by-
Hallucination with distress Hallucination without distress moment sensory input with stored memory
(OR; 95% CI), frequency1 (OR; 95% CI), frequency1 (Hemsley, 1993, 1994). A neuronal
circuit, including the limbic system, is
proposed to be involved in this integration
Unadjusted
process. Distress can lead to an increased
T2: BPRS 25.0 (9.3^67.8) 4.9 (2.0^11.9) 5.2 1 0.02
dopamine release that in turn may influence
delusion 41 6/32 7/161
the functioning of these brain structures
T2: BPRS 50.4 (14.9^169.9) 0.9 (0.1^7.8) 8.7 1 0.003
(Robinson & Becker, 1986). Thus, a
delusion 42 4/32 1/161
stress-induced dopaminergic response in
T2: BPRS 126.4 (26.8^595.3) ^2 ^ ^ ^
humans could result in a heightened risk
delusion 43 3/32 0/161
Adjusted for positive psychotic symptoms in vulner-
T2: BPRS 13.7 (4.4^42.4) 3.2 (1.2^8.4) 3.8 1 0.05 able persons, with possible subsequent sen-
delusion 41 sitisation of dopaminergic response and
+covariates persistence of delusional ideation (Laruelle,
T2: BPRS 25.1 (4.8^131.3) 0.5 (0.04^4.9) 8.5 1 0.004 2000).
delusion 42 In summary, the present findings have
+covariates implications for early intervention in psy-
T2: BPRS 136.2 (13.1^1414.3) ^2 ^ ^ ^ chosis or psychosis-like experiences, and
delusion 43 underline the significance of cognitive–
+covariates behavioural therapy in treating psychotic
disorders (Kingdon & Turkington, 1994;
BPRS, Brief Psychiatric Rating Scale.
1. Frequency means the number of individuals with delusion formation given the number of individuals with lifetime Turkington & Kingdon, 2000). If distress
hallucinations with or without distress. associated with hallucinations is involved
2. Predicts failure perfectly.
in the development of delusions, ameliorat-
CI 5.6–60.2) and for baseline hallucina- by hallucinatory experiences may in turn be ing the distress may prevent the formation
tions without distress (OR¼5.4, 95% CI
(OR 5.4, related to the interpretation of the experi- of delusions in some individuals.
2.1–14.3), indicating a similar pattern of ence (Morrison & Baker, 2000). The Cognitive–behavioural, anxiety-reducing
results. mechanism of delusion formation may and reappraisal techniques could be instru-
depend on the initial interpretation indivi- mental in preventing the development of
DISCUSSION duals give to their unusual perceptual intru- delusions in those with anomalous experi-
sions. If this initial interpretation leads to al,
ences (McGorry et al, 2002; Morrison et
The results show that those who experience distress, the individual may be more prone al,
al, 2002).
negative emotional states associated with to selective attentional processes and safety However, this work should be in-
anomalous perceptual intrusions have a behaviours, diminishing the opportunity to terpreted in the light of several potential
much greater risk of developing delusional test the accuracy of the psychotic experi- limitations. First, distress was operationa-
ideation, including experiences of al,
ence (Garety et al, 2001), resulting in lised as feeling disturbed by the hallucina-
clinical relevance, than individuals who increased levels of delusional ideation. tions and/or displaying help-seeking
report similar experiences without distress. The role of distress associated with behaviour. Thus, the mediating role of dis-
Individuals reporting distress associated unusual experiences may also be crucial to tress in the development of delusions is a
with their hallucinations did show a much understand further transitions over the psy- general one, as we did not have any infor-
greater risk for developing clinical delu- chosis continuum. Peters et al (1999) mea- mation linking distress to content of or
sions than those reporting hallucinations sured delusional ideation in the general beliefs about hallucinations and/or delu-
without distress. Our findings support the population as well as in those with delu- sions. Second, differential attrition in this
amplifying role of distress in current cogni- sions using the Peters et al Delusions Inven- longitudinal design could have biased the
tive models of delusion formation (Freeman tory (PDI). The PDI scores of the general results. However, sensitivity analyses gener-
& Garety, 1999; Birchwood et al, 2000;
al, population and the patients with delusions ated essentially similar results. Third, the
Morrison & Baker, 2000; Garety et al, al, showed a large degree of overlap and nearly present study monitored only one of the
2001). According to these models, feelings 10% of the general population scored many mediating and maintaining factors
of uncontrollability and hopelessness asso- above the mean of the group with delu- proposed by Garety et al (2001). However,
ciated with negative emotional states may sions. However, compared with patients, it was not possible to examine the role of
contribute to the onset of delusional inter- the general population displayed signifi- many other important variables in the
pretations. Emotions may also make hallu- cantly less distress, preoccupation and con- formation of delusions (e.g. externalising
cinatory experiences personally significant viction regarding their unusual perceptual attributional biases, problems with self-
or more intrusive, which in turn may experiences and ideas. monitoring, dysfunctional schemas etc.),
trigger the individual to search for explana- The present study is limited to psycho- as we did not gather this information.
tions of the experiences. The distress caused logical factors, but biological factors may Finally, the outcome ‘unusual thought
s57
HANS S EN E T AL
content’ was very rare, affecting the preci-
sion with which we could estimate effect
CLINICAL IMPLICATIONS
sizes.
& Psychotic experiences are common and transitions to clinical disorder are in part
ACKNOWLEDGEMENTS determined by emotional factors.
This study was funded by the Dutch Department of & Not only the presence of an unusual perceptual experience in itself but also the
Health. emotional appraisal by the subject is an important risk factor for subsequent delusion
formation.
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