Psychiatric Explanations of Poor Oral Intake: A Clinically Focused Review

Background: Poor oral intake (POI) among medical-surgical inpatients can cause malnutrition and delay recovery due to medical consequences and the need for more invasive nutritional support. Many psychiatric conditions can cause POI; however, the role that psychiatric conditions play in POI has received limited attention to date.

Objective: This review aggregates available information on POI due to psychiatric conditions and provides a framework for the clinical approach to these conditions in hospitalized adult patients.

Methods: We searched PubMed and EMBASE for reviews of POI due to psychiatric causes, but no relevant publications were identified. Diagnostic criteria for relevant conditions in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision and Rome IV were reviewed, as were C-L psychiatry textbooks and relevant society websites. This review was further supplemented by a case conference at the authors' institution.

Results: We have divided results into five sections for clinical utility: (1) the need to rule out medical causes of POI; (2) unpleasant somatic experiences, including psychotropic causes; (3) mood, psychotic, catatonic, and neurocognitive disorders that can present with POI; (4) eating and feeding disorders; and (5) personal and interpersonal explanations of POI. Within each section, we review how to identify and manage each condition, specifically considering the effects of treatment on oral intake.

Conclusions: The clinical management of POI varies based on cause. For instance, psychostimulants can cause POI due to inappetence; however, they can treat POI due to abulia by improving motivation. The fact that such a broad range of psychiatric conditions can cause POI calls for a systematic clinical approach that considers the categories of potential causes. We also identified a need for prospective studies focused on the management of POI due to psychiatric conditions, as the literature on this topic is limited to case reports, case series, and retrospective cohort studies.