Recorded atypical hallucinations in psychotic and affective disorders and associations with non-benzodiazepine hypnotic use: the South London and Maudsley Case Register.
OBJECTIVES
Hallucinations are present in many conditions, notably psychosis. Although under-researched, atypical hallucinations, such as tactile, olfactory and gustatory (TOGHs), may arise secondary to hypnotic drug use, particularly non-benzodiazepine hypnotics ('Z drugs'). This retrospective case-control study investigated the frequency of TOGHs and their associations with prior Z drug use in a large mental healthcare database.


METHODS
TOGHs were ascertained in 2014 using a bespoke natural language processing algorithm and were analysed against covariates (including use of Z drugs, demographic factors, diagnosis, disorder severity and other psychotropic medications) ascertained prior to 2014.


RESULTS
In 43 339 patients with International Classification of Diseases, Tenth Edition schizophreniform or affective disorder diagnoses, 324 (0.75%) had any TOGH recorded (0.54% tactile, 0.24% olfactory, 0.06% gustatory hallucinations). TOGHs were associated with male gender, black ethnicity, schizophreniform diagnosis and higher disorder severity on Health of the National Outcome Scales. In fully adjusted models, tactile and olfactory hallucinations remained independently associated with prior mention of Z drugs (ORs 1.86 and 1.60, respectively).


CONCLUSIONS
We successfully developed a natural language processing algorithm to identify instances of TOGHs in the clinical record. TOGHs overall, tactile and olfactory hallucinations were shown to be associated with prior mention of Z drugs. This may have implications for the diagnosis and treatment of patients with comorbid sleep and psychiatric conditions.
['Birnie|Karen Isabel|KI|', 'Stewart|Robert|R|', 'Kolliakou|Anna|A|']
D000293:Adolescent D000328:Adult D000368:Aged D000465:Algorithms D016022:Case-Control Studies D005260:Female D006212:Hallucinations D006801:Humans D006993:Hypnotics and Sedatives D016015:Logistic Models D008131:London D008297:Male D008875:Middle Aged D019964:Mood Disorders D012042:Registries D012189:Retrospective Studies D012559:Schizophrenia D012903:Smell D014110:Touch D055815:Young Adult
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