Diagnostic visibility and context-dependent referral patterns in consultation-liaison psychiatry: A ten-year...

We examined whether psychiatric referral patterns in a general hospital without dedicated psychiatric beds are associated with symptom visibility rather than the underlying burden of psychiatric morbidity, and whether this pattern varies by clinical context.

A ten-year retrospective descriptive study (FY2016-2025) was conducted at Kakogawa Central City Hospital, a 600-bed public hospital serving as a Regional Dementia Medical Centre. Three inpatient psychiatric intervention routes were analysed: psychiatrist-led first assessments (n = 7991; diagnostic analyses restricted to n = 7522 with individual diagnostic records), Liaison Team consultations (n = 6610), and Dementia Care Team interventions (n = 4810; total 19,411). Diagnoses were categorised using a visibility framework: Visible disorders (delirium [F05]; neurocognitive disorders [F00-03]) versus Less visible disorders (depression [F30-32]; anxiety [F40-48]; adjustment disorder [F43]). Departmental variation was examined using chi-square analysis across ten referring departments.

Liaison Team consultations increased from 299 to 911 and Dementia Care Team interventions from 117 to 846 over ten years. Among 7522 assessments with individual diagnostic records (FY2017-2025), Visible disorders accounted for 67.7% (n = 5091), with delirium alone comprising 57.6% (n = 4336). Less visible disorders represented only 12.9% (n = 971), yielding a Visible-to-Less visible ratio of 5.2:1. This ratio was consistent across all sensitivity analyses (range: 5.2-5.8:1). Marked departmental variation was observed (χ²(18) = 845.0, p < 0.001): the ratio ranged from ∼16:1 in cardiac surgery to 0.1:1 in obstetrics and gynaecology.

Psychiatric referral patterns are more closely associated with symptom visibility than with the likely underlying burden of psychiatric morbidity, consistent with relative under-referral of affective disorders. This pattern is context-dependent: the inverse pattern in obstetrics suggests that referral behaviour may be shaped by clinical setting rather than disorder prevalence.