Illness Attitudes Questionnaire

Abstract

The Illness Attitudes Questionnaire (IAQ) is a premier self-report psychometric instrument developed by Robert Kellner in 1986 to assess the multidimensional attitudes, fears, beliefs, and behavioral tendencies associated with hypochondriasis and abnormal illness behavior. Originally devised to provide a nuanced diagnostic and evaluative tool distinct from unidimensional measures, the IAQ comprises 29 items distributed across nine conceptually derived subscales: Worry about illness, Concern about pain, Health habits, Hypochondriacal beliefs, Thanatophobia, Disease phobia, Bodily preoccupations, Treatment experience, and Effects of symptoms. Items are traditionally scored on a 5-point Likert scale ranging from 0 (“No”) to 4 (“Most of the time”), yielding both subscale profiles and an aggregate total score reflecting overall health anxiety severity. Extensive psychometric evaluations over nearly four decades demonstrate that the IAQ possesses robust internal consistency (total scale α typically ranging from .88 to .94), satisfactory test-retest reliability across intervals ranging from one to four weeks (r = .75–.90), and strong convergent validity with related indices such as the Whiteley Index, the Somatosensory Amplification Scale (SSAS), and the Health Anxiety Inventory (HAI). Furthermore, the instrument exhibits robust discriminant validity, differentiating clinical hypochondriacal cohorts from medical patients with verifiable organic pathologies, general psychiatric outpatients, and non-clinical populations. Factor analytic investigations have elucidated both Kellner’s original nine-factor conceptual framework and refined empirical structures (such as two-, three-, and four-factor models capturing Health Anxiety, Illness Behavior, and Symptom Disruption), affirming its adaptability in contemporary psychiatric, psychosomatic, and behavioral medicine research.

Keywords

Illness Attitudes Questionnaire, IAQ, health anxiety, hypochondriasis, somatic symptom disorder, illness anxiety disorder, somatosensory amplification, Robert Kellner, psychometrics, illness behavior, bodily preoccupation, thanatophobia

Authors

The Illness Attitudes Questionnaire was designed and validated by Robert Kellner, M.D., Ph.D. (1922–1992), a distinguished psychosomatic researcher and Professor of Psychiatry at the Department of Psychiatry, School of Medicine, University of New Mexico, Albuquerque, New Mexico, USA. Dr. Kellner was an internationally recognized authority on somatization, somatic symptoms in psychiatric disorders, and the clinical pharmacology of functional somatic syndromes. In subsequent psychometric refinement and cross-cultural validation studies, Kellner collaborated with notable psychometricians and clinical researchers, including K. Winslow, P. J. Pathak, and R. J. Abbott. Later empirical structural evaluations and cognitive-behavioral adaptations have been conducted by academic clinical researchers including Gordon J. G. Asmundson, Heather D. Hadjistavropoulos, Eamonn Ferguson, and Paul M. Salkovskis.

Purpose

The fundamental purpose of the Illness Attitudes Questionnaire is to capture and quantify the cognitive, affective, and behavioral manifestations that define an individual’s orientation toward physical illness, health risks, and somatic sensations. Clinically, health anxiety exists on a broad continuum, ranging from benign, adaptive vigilance regarding bodily well-being to severe, debilitating psychopathology historically categorized as hypochondriasis in the Diagnostic and Statistical Manual of Mental Disorders (DSM-III and DSM-IV) and currently conceptualized within DSM-5 as Illness Anxiety Disorder and Somatic Symptom Disorder. Prior to the introduction of the IAQ, existing instruments such as the Hypochondriasis scale of the Minnesota Multiphasic Personality Inventory (MMPI-Hs) primarily indexed reported somatic symptoms rather than the cognitive schemata, catastrophic misinterpretations, and maladaptive illness behaviors that maintain hypochondriacal anxiety.

Kellner formulated the IAQ to address this diagnostic and psychometric void. The scale was purposefully engineered to delineate the distinct psychological components of abnormal illness attitudes, thereby allowing researchers and clinicians to:

• Screen for Severe Health Anxiety: Rapidly identify individuals in primary care, specialized medical clinics (e.g., cardiology, neurology, gastroenterology), and psychiatric settings whose primary distress stems from catastrophic disease convictions rather than underlying organic disease.
• Differential Diagnosis: Distinguish between authentic somatic pathology, functional somatic syndromes, generalized anxiety disorder, panic disorder, and specific somatic delusions or obsessive-compulsive manifestations.
• Evaluate Treatment Efficacy: Serve as a sensitive pre-, mid-, and post-intervention outcome measure in clinical trials assessing cognitive-behavioral therapy (CBT), exposure and response prevention, mindfulness-based interventions, and pharmacotherapy (such as selective serotonin reuptake inhibitors).
• Profile Maladaptive Behaviors: Quantify excessive reassurance-seeking, repeated medical consultations (“doctor shopping”), diagnostic overutilization, somatic hyper-checking, and counter-phobic avoidance of medical information or disease-related cues.
• Investigate Etiological Mechanisms: Facilitate empirical research into cognitive vulnerabilities, such as intolerance of uncertainty, fear of death (thanatophobia), and somatosensory amplification, across medical sociology and clinical health psychology.

Psychological Construct

The Illness Attitudes Questionnaire operationalizes the psychological construct of hypochondriacal attitudes and illness behavior. Rather than treating hypochondriasis as a monolithic diagnostic entity, Kellner postulated that illness anxiety represents an interconnected matrix of cognitive biases, emotional distress, physiological hyper-responsiveness, and overt behavioral adaptations. The IAQ dissects this overarching construct into nine specific psychological dimensions:

1. Worry about Illness

This dimension reflects pervasive, intrusive, and distressing cognitions concerning current or future medical vulnerability. Individuals scoring high on this subscale experience recurrent worries about developing severe physical conditions (e.g., cardiovascular events, neurodegenerative diseases), are readily alarmed by health-related news, and perceive serious illness as an impending, inevitable catastrophe.

2. Concern about Pain

This subscale evaluates pain catastrophizing and somatic hyper-vigilance. It measures the degree to which an individual interprets benign or transient nociceptive sensations as definitive indicators of dangerous underlying tissue damage or systemic disease (e.g., believing that a tension headache signifies an intracerebral neoplasm or that a localized muscular twinge represents a terminal disorder).

3. Health Habits

Health Habits assesses the self-protective, preventive, and health-promotive behavioral routines engaged in by the respondent. Unlike other subscales, this dimension captures adaptive or compensatory actions, such as rigorous dietary maintenance, structured physical exercise regimens, stress management practices, and proactive consumption of literature regarding wellness and physical fitness.

4. Hypochondriacal Beliefs

Representing the core cognitive conviction of hypochondriasis, this dimension indexes epistemic mistrust toward medical professionals and entrenched disease conviction. It captures an individual’s refusal to accept medical reassurance, the persistent belief that physicians have failed to detect an elusive, life-threatening malady, and the conviction that negative diagnostic evaluations represent laboratory error rather than genuine physical health.

5. Thanatophobia

Thanatophobia measures explicit death anxiety and existential panic tied to mortality. It captures an intense, paralyzing dread of dying, persistent intrusions regarding the brevity of life, and terror elicited by encounters with mortality, burial environments, or terminal disease trajectories.

6. Disease Phobia

This subscale measures phobic avoidance behaviors and marked anxiety triggered by illness-related external stimuli. Respondents exhibiting high disease phobia actively avoid medical publications, healthcare broadcasts, conversations about pathology, or physical proximity to hospitals and sick individuals due to an intense fear that exposure will induce symptoms or contaminate them.

7. Bodily Preoccupations

Bodily Preoccupations indexes selective attention and somatosensory hyper-vigilance directed toward internal physiological processes. It evaluates the respondent’s tendency to continuously scan, monitor, palpate, and visually inspect their body for physiological asymmetries, dermatological variations, minor visceral shifts, or autonomic fluctuations, accompanied by an inability to disengage attention from internal bodily cues.

8. Treatment Experience

This behavioral subscale quantifies healthcare utilization patterns over the preceding 12-month period. It captures the frequency of outpatient physician visits, consultations with multiple medical specialists, and exposure to repeated diagnostic workups, imaging studies, and therapeutic regimens.

9. Effects of Symptoms

This dimension assesses functional impairment and secondary disability secondary to subjective somatic distress. It evaluates the extent to which somatic sensations interfere with occupational productivity, interpersonal relationships, leisure activities, and ordinary daily responsibilities.

Theoretical Framework

The Illness Attitudes Questionnaire is grounded in an integration of psychosomatic medicine, somatosensory amplification theory, and cognitive-behavioral models of health anxiety.

Historically, early psychoanalytic formulations conceptualized hypochondriasis as a narcissistic neurosis or a symbolic defense mechanism wherein repressed intrapsychic conflict or hostile impulses were transformed into somatic complaints. In contrast, Robert Kellner approached illness attitudes from an empirical psychosomatic perspective. Kellner proposed that individuals prone to hypochondriasis exhibit enduring cognitive schema characterized by hyper-reactivity to benign physiological variations, an inaccurate baseline model of human physiology (viewing healthy bodies as completely noiseless, symmetrical, and free from any sensations), and catastrophic interpretive tendencies.

The theoretical architecture of the IAQ aligns closely with the Somatosensory Amplification model articulated by Arthur Barsky. According to this framework, somatosensory amplification consists of three interrelated components: (a) hyper-vigilance and selective bodily scanning; (b) a perceptual predisposition to select and focus on weak, infrequent sensations; and (c) a cognitive tendency to appraise these normal or trivial physiological sensations as pathological, dangerous, and indicative of disease. The IAQ operationalizes this dynamic across its Bodily Preoccupations, Concern about Pain, and Hypochondriacal Beliefs subscales.

Furthermore, the IAQ is congruent with the cognitive-behavioral conceptualization advanced by Warwick and Salkovskis. In this cognitive model, dysfunctional conditional and unconditional assumptions (e.g., “If a bodily sensation cannot be explained immediately, it must be fatal,” or “Doctors frequently miss subtle tumors”) govern the appraisal of internal and external stimuli. When triggered by a physiological change (e.g., benign palpitations, localized tension), these schemata generate negative automatic thoughts, escalating autonomic arousal through sympathetic activation. This autonomic surge produces additional bodily sensations, creating a vicious maintenance cycle. Maladaptive safety-seeking behaviors (such as frequent medical consultations, reassurance-seeking, or excessive self-examination) paradoxically reinforce health anxiety by preventing cognitive disconfirmation and maintaining attentional focus on physiological processes.

Validity

Extensive psychometric investigations across international clinical and non-clinical populations have established strong validity evidence for the Illness Attitudes Questionnaire.

Construct and Convergent Validity

The IAQ exhibits high convergent validity when evaluated against established measures of health anxiety and somatic preoccupation. In seminal validation cohorts conducted by Kellner (1986, 1987), aggregate IAQ scores demonstrated substantial positive correlations with the Whiteley Index (r values ranging between .65 and .81) and the Hypochondriasis clinical scale of the MMPI (r = .52 to .68). In contemporary studies comparing the IAQ with modern psychometric instruments, IAQ total scores correlate strongly with the Health Anxiety Inventory (HAI; r = .74 to .85) and the Somatosensory Amplification Scale (SSAS; r = .55 to .64). Individual subscales demonstrate theoretically predicted convergences; for instance, the Concern about Pain subscale correlates robustly with the Pain Catastrophizing Scale (PCS; r = .60), while Thanatophobia correlates significantly with Templer’s Death Anxiety Scale (r = .68).

Discriminant and Criterion Validity

The IAQ possesses remarkable discriminant validity, successfully differentiating clinical populations with hypochondriasis (Illness Anxiety Disorder / Somatic Symptom Disorder) from other clinical cohorts and healthy controls. In Kellner’s early studies, patients formally diagnosed with DSM-III hypochondriasis scored significantly higher on eight of the nine subscales (excluding Health Habits) than did healthy control subjects, psychiatric patients with major depressive or generalized anxiety disorders, and medical patients suffering from confirmed organic medical illnesses (e.g., rheumatoid arthritis, stable ischemic heart disease). Medical patients typically endorse symptoms and physician visits (Treatment Experience) but do not endorse marked Hypochondriacal Beliefs, Disease Phobia, or Bodily Preoccupations, demonstrating that the IAQ measures psychological orientation rather than the mere presence of objective medical disease.

Predictive and Sensitivity to Treatment

The instrument has repeatedly proven sensitive to clinical change in pharmacological and psychotherapeutic intervention trials. Reductions in IAQ total scores, particularly across the Worry about Illness, Bodily Preoccupations, and Hypochondriacal Beliefs subscales, systematically track clinical improvement following manualized cognitive-behavioral therapy for health anxiety, showing moderate-to-large effect sizes (Cohen’s d = 0.80 to 1.45) that correspond with reductions in excessive medical service utilization.

Reliability

The Illness Attitudes Questionnaire exhibits excellent reliability across a broad spectrum of psychometric evaluations.

Internal Consistency

Across diverse clinical and community samples, the total IAQ scale demonstrates high internal consistency, with Cronbach’s alpha coefficients routinely exceeding .88 and frequently falling between .90 and .94. At the subscale level, internal consistency estimates vary somewhat due to differences in subscale length:

• Worry about Illness (3 items): α = .78 to .84
• Concern about Pain (2 items): α = .68 to .76
• Health Habits (3 items): α = .55 to .66 (reflecting the behavioral heterogeneity of dietary, exercise, and reading habits)
• Hypochondriacal Beliefs (3 items): α = .72 to .81
• Thanatophobia (2 items): α = .76 to .85
• Disease Phobia (3 items): α = .70 to .79
• Bodily Preoccupations (4 items): α = .75 to .83
• Treatment Experience (3 items): α = .65 to .74
• Effects of Symptoms (3 items): α = .74 to .82

Test-Retest Reliability

Temporal stability assessments demonstrate that illness attitudes represent relatively stable psychological traits in the absence of targeted psychological intervention. Over a 1-week test-retest interval, Kellner reported correlation coefficients for subscales ranging from .75 to .90, with the total score correlation exceeding .90. In non-clinical collegiate and community cohorts re-evaluated across four-week to six-week intervals, test-retest reliability remained robust (total score intraclass correlation coefficient [ICC] = .82 to .87), confirming that the instrument reliably captures enduring cognitive-affective schemata while retaining the sensitivity needed to detect meaningful therapeutic change.

Factor Analysis

Although Robert Kellner structured the IAQ around nine rationally and clinically derived subscales, subsequent structural equation modeling, exploratory factor analyses (EFA), and confirmatory factor analyses (CFA) have yielded valuable empirical insights into its underlying latent dimensions.

Kellner’s Original 9-Factor Conceptual Structure

Kellner’s initial 9-factor model was derived from clinical observations of hypochondriacal symptom presentation. However, because several subscales contain only two or three items, psychometricians have noted that some subscales share high intercorrelations (e.g., Worry about Illness, Disease Phobia, and Bodily Preoccupations frequently correlate between r = .55 and .70), leading investigators to explore more parsimonious latent structures.

Empirical Factor Models

Subsequent psychometric investigations have proposed several alternative factor structures to optimize model fit and parsimony:

• Ferguson’s Four-Factor Solution (2000): In a large non-clinical investigation (N = 642), Eamonn Ferguson conducted principal components analysis with varimax rotation, identifying four robust, replicable factors: (1) Health Anxiety (combining Worry about illness, Bodily preoccupations, and Thanatophobia), (2) Illness Behavior (combining Treatment experience and Effects of symptoms), (3) Hypochondriacal Beliefs (reflecting medical skepticism and disease conviction), and (4) Health Habits. This four-factor structure demonstrated acceptable goodness-of-fit indices (CFI > .90, RMSEA < .06).
• Stewart and Watt’s Three-Factor Solution (2000): Investigating the structural validity across both community and clinical samples, Stewart and Watt demonstrated that the IAQ items could be elegantly captured by three higher-order latent factors: (1) Fears and Worries (emotional and cognitive dread regarding illness and death), (2) Beliefs and Disruption (disease conviction and impairment of daily function), and (3) Healthcare Utilization and Monitoring.
• Hadjistavropoulos et al. Two-Factor Model (1999): Analyzing clinical pain and hypochondriacal outpatients, Hadjistavropoulos and colleagues identified a broad, overarching two-factor model consisting of: (1) Core Health Anxiety (subsuming the cognitive, phobic, and bodily preoccupation items), and (2) Illness Behavior and Functional Disability (subsuming physician visits, disability, and role impairment).

Confirmatory factor analytic studies generally indicate that while Kellner’s original 9-factor model has high face and clinical utility, modified 3-factor or 4-factor models typically achieve superior parsimony and goodness-of-fit indices in cross-validation cohorts, confirming that health anxiety manifests as a coordinated system of cognitive worry, somatic amplification, and behavioral utilization.

Instrument / Measurement Tool

The Illness Attitudes Questionnaire is an administratively efficient, self-report psychometric test designed for clinical assessment and empirical research.

• Instrument Name: Illness Attitudes Questionnaire (IAQ)
• Original Developer: Robert Kellner, M.D., Ph.D. (1986)
• Administration Format: Paper-and-pencil self-administered questionnaire, digital survey interface, or clinician-facilitated interview.
• Target Population: Adults and adolescents aged 16 years and older; suitable for psychiatric, primary care, specialized medical, and community samples.
• Completion Time: Approximately 5 to 10 minutes.
• Item Count: 29 discrete items.
• Subscales (9 Dimensions):
  • Worry about illness: Items 1, 2, 3
  • Concern about pain: Items 4, 5
  • Health habits: Items 27, 28, 29
  • Hypochondriacal beliefs: Items 13, 14, 15
  • Thanatophobia: Items 16, 17
  • Disease phobia: Items 6, 7, 8
  • Bodily preoccupations: Items 9, 10, 11, 12
  • Treatment experience: Items 24, 25, 26
  • Effects of symptoms: Items 21, 22, 23
• Response Scale (Mandatory Formats):
  • Authentic Original 5-Point Likert Scale: 0 = No, 1 = Rarely, 2 = Sometimes, 3 = Often, 4 = Most of the time
  • Modified Cognitive Therapy Format (Alternative): 7-point agreement scale: Totally Agree, Agree Very Much, Agree Slightly, Neutral, Disagree Slightly, Disagree Very Much, Totally Disagree
• Scoring Procedures:
  • Subscale scores are obtained by summing the numerical ratings assigned to their constituent items.
  • Total IAQ score is calculated by summing the subscale scores (total theoretical score ranges from 0 to 116 when using the standard 0–4 scoring). In some clinical and research applications, the Health Habits subscale (Items 27–29) is evaluated independently or excluded from the total health anxiety composite, as high scores on health habits can reflect adaptive wellness practices rather than pathological anxiety.
• Clinical Cut-Offs: Total scores exceeding 45–50 on the 26-item pathological composite (excluding Health Habits) generally indicate clinically significant health anxiety warranting comprehensive diagnostic assessment for Illness Anxiety Disorder or Somatic Symptom Disorder.

Permissions & Fee and Test Year

The Illness Attitudes Questionnaire was originally published in 1986 by Dr. Robert Kellner in the seminal article titled “Somatization and Hypochondriasis” and further detailed in the 1987 publication “Abridged Illness Attitudes Questionnaire” in the Journal of Psychosomatic Research. The instrument is generally considered to reside in the academic public domain for non-commercial educational, scientific, and clinical research purposes, provided that appropriate scholarly attribution is accorded to Dr. Robert Kellner and the primary publication sources. Commercial publishers, digital assessment platforms, or organizations incorporating the scale into proprietary clinical decision-support software should verify copyright conditions with the original publisher (Elsevier / Pergamon Press) or the academic estate of Dr. Robert Kellner through the University of New Mexico School of Medicine. No standardized per-test licensing fee is mandated for individual academic or clinical use.

References

• Barsky, A. J., & Klerman, G. L. (1983). Overview: Hypochondriasis, bodily complaints, and somatic styles. American Journal of Psychiatry, 140(3), 273–283. https://doi.org/10.1176/ajp.140.3.273
• Ferguson, E. (2000). The Illness Attitudes Questionnaire: Test-retest reliability and factor structure in a non-clinical student sample. Journal of Psychosomatic Research, 49(5), 363–369. https://doi.org/10.1016/S0022-3999(00)00181-4
• Hadjistavropoulos, H. D., Frombach, I. K., & Asmundson, G. J. (1999). Exploratory and confirmatory factor analyses of the Illness Attitudes Questionnaire in a nonclinical sample. Behaviour Research and Therapy, 37(12), 1219–1232. https://doi.org/10.1016/S0005-7967(99)00030-8
• Kellner, R. (1986). Somatization and hypochondriasis. Praeger Publishers.
• Kellner, R. (1987). A symptom questionnaire. The Journal of Clinical Psychiatry, 48(7), 268–274.
• Kellner, R., Abbott, R., Winslow, W. W., & Pathak, D. (1987). Fears, beliefs, and attitudes in DSM-III hypochondriasis. The Journal of Nervous and Mental Disease, 175(1), 20–25. https://doi.org/10.1097/00005053-198701000-00004
• Salkovskis, P. M., Rimes, K. A., Warwick, H. M. C., & Clark, D. M. (2002). The Health Anxiety Inventory: Development and validation of scales for the measurement of health anxiety and hypochondriasis. Psychological Medicine, 32(5), 843–853. https://doi.org/10.1017/S0033291702005822
• Stewart, S. H., & Watt, M. C. (2000). Illness attitudes in panic disorder and anxiety sensitivity. Journal of Psychosomatic Research, 49(6), 407–418. https://doi.org/10.1016/S0022-3999(00)00192-9
• Warwick, H. M., & Salkovskis, P. M. (1990). Hypochondriasis. Behaviour Research and Therapy, 28(2), 105–117. https://doi.org/10.1016/0005-7967(90)90023-C

Items of the Scale