Clinical correlates of olfactory hallucinations in schizophrenia

Br J Clin Psychol. 2011 Jun;50(2):145-63. doi: 10.1348/014466510X500837. Epub 2011 Feb 23.


OBJECTIVES. Olfactory hallucinations (OHs) are underrepresented in conventional clinical instruments, infrequently researched, and poorly understood. To advance understanding of OHs, we examined their past-month prevalence and co-occurring symptoms in two datasets. DESIGN. One dataset comprised categorical codes and was examined using homogeneity analysis and logistic regression; the other dataset comprised numeric ratings and was examined using principal components analyses and linear regression. METHOD. The two datasets included: (1) 962 cases with Present State Examination - 9th Edition (PSE-9), codes (recoded present/absent) from the World Health Organization 10 Country (WHO-10) Study and (2) 265 cases with ratings on Scales for Assessing Positive/Negative Symptoms of Schizophrenia (SAPS/SANS). Two PSE-9 items (external- and self-smells) were recoded into a single OH item to examine consistency with the SAPS/SANS dataset, which contained a single OH item. RESULTS. Prevalence of OHs and hallucinations in other modalities differed according to the WHO-10 international centre. Across centres, OHs were present in 13% of the WHO-10 dataset, similar to the 17% prevalence rate in the SAPS/SANS dataset. Referential/control delusions and other hallucinations (particularly, somatic/tactile/gustatory hallucinations) were significant independent correlates of OHs in both datasets. OHs also co-occurred with social anxiety and depression in the WHO-10 dataset, with self-smells being particularly associated with self-depreciation. CONCLUSIONS. Sociocultural factors may modulate the self-reporting and/or detection of OHs and hallucinations in other modalities. Referential/control delusions promote the generation and/or maintenance of OHs independent of factors shared with other hallucinations. OHs and hallucinations of taste, touch, and bodily sensation frequently co-occur. Self-smells warrant sensitive probing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anxiety Disorders / diagnosis
  • Anxiety Disorders / epidemiology
  • Anxiety Disorders / psychology
  • Chronic Disease
  • Comorbidity
  • Cross-Cultural Comparison
  • Cross-Sectional Studies
  • Delusions / diagnosis
  • Delusions / epidemiology
  • Delusions / psychology
  • Depressive Disorder / diagnosis
  • Depressive Disorder / epidemiology
  • Depressive Disorder / psychology
  • Female
  • Hallucinations / diagnosis*
  • Hallucinations / epidemiology
  • Hallucinations / psychology*
  • Humans
  • Male
  • Mental Status Schedule / statistics & numerical data
  • Middle Aged
  • Phobic Disorders / diagnosis
  • Phobic Disorders / epidemiology
  • Phobic Disorders / psychology
  • Psychiatric Status Rating Scales / statistics & numerical data
  • Psychometrics / statistics & numerical data
  • Reproducibility of Results
  • Schizophrenia / diagnosis*
  • Schizophrenia / epidemiology
  • Schizophrenic Psychology*
  • Self Concept
  • Smell*
  • World Health Organization
  • Young Adult