Analysis of inedible substance ingestion at a Japanese psychiatric hospital.

Background: Inedible substance ingestion increases the risk of ileus, poisoning, and suffocation. Prevention is especially important in a psychiatric setting. This study aimed to analyze the incidence of inedible substance ingestion in a Japanese psychiatric hospital.

Methods: Inedible substance ingestion incidents were extracted from an incident report database spanning 2000-2012 at a 400-bed psychiatric hospital in Japan. We tabulated the frequencies of incidents in accordance with major diagnosis, ingested materials, incident levels, and time of occurrence.

Results: The incidence rate was 0.09/1000 patient days, and 149 cases in 105 patients were classified as having experienced inedible substance ingestion. The most common diagnosis was dementia (n = 58), followed by schizophrenia (n = 22). Materials ingested by dementia patients were nappies or gauze attached to the patient's body after medical procedures. Materials ingested by schizophrenic patients were liquid soap, detergent or shampoo, and cigarettes. Inedible substance ingestion among dementia patients occurred mostly before or during meals. Among schizophrenic patients, the peak period of incidents was in the evening.

Conclusions: Dementia patients were overrepresented in the inedible substance ingestion incidents. Items they wore or applied to their bodies were often subject to ingestion, and such behaviours mostly occurred around meal time. Therefore, the nursing staff were able to discover them quickly and treat most of the cases free of serious consequences. In contrast, schizophrenic patients were underrepresented in the incidents, and most cases involved ingestion of detergent powder or cigarettes, resulting in more serious consequences and requiring treatment.