Consultation-liaison psychiatry

Topic

Psychiatry inside the general hospital: helping medical and surgical teams with delirium, depression, capacity and other problems.

Updated Nov 13, 2026

Key points

Delirium is the most common reason for hospital psychiatric referral in published series and is often overlooked; the hyperactive form is often mistaken for psychosis.
The first step is direct communication with the referring doctor to understand the real question, such as ‘can this patient refuse surgery?’.
Depression in medically ill patients is common, affects the overall outcome and often presents as somatic distress.
Decision-making capacity rests on four abilities: understanding, appreciation, reasoning and expressing a clear, consistent choice; the level needed rises with the stakes of the decision.
Do not lean toward dissociative or conversion symptoms from the outset: underlying organic conditions are looked for first.
Recommendations are communicated directly to the treating doctor, at least by phone, and the patient is followed up, at least within a week.

What it is

Consultation-liaison psychiatry is the branch of psychiatry that works with patients admitted to general hospital wards and their teams. In consultation, the psychiatrist answers a specific question about one patient; in liaison, the psychiatrist works regularly with a team to improve care, train staff and prevent problems. In published series, delirium is the most common reason for referral, followed by substance use disorders; depression, anxiety, self-harm and physical symptoms without a clear medical explanation are also frequent.

Step by step

Talk directly with the referring doctor to understand how they see the case and what the real question is.
Review the chart, the ongoing treatment and the nursing staff’s observations.
Introduce yourself carefully: a psychiatric interview is often unexpected for the patient and relatives, so build rapport first.
Assess mood, anxiety and substance use and, after any self-harm, suicidal intent.
Examine attention and screen for delirium, the most common reason for referral.
Write a short formulation: likely diagnosis, link with the medical illness, interactions with the ongoing treatment and immediate risk.
Communicate the recommendations directly to the treating doctor, at least by phone, and follow up, at least within a week.

Common referral questions and what to check first

Referral question	Check first
Confused or ‘psychotic’ patient	Attention, fluctuation, infection, hypoxia, metabolic causes, medicines: think delirium
‘Depressed’ patient	Hypoactive delirium, and medical illness that can present as depression (such as pancreatic cancer); then screen for depression
Can the patient refuse treatment?	The four abilities of capacity: understanding, appreciation, reasoning and a clear choice
Agitation days after admission	Alcohol or other substance withdrawal, delirium
After a suicide attempt	Medical stabilisation first, then a detailed interview on suicidal intent
Symptoms without a medical explanation	A complete medical review first, without leaning early toward a dissociative or conversion explanation

Clinical notes

Depression in the medically ill often presents with somatic distress, and some medical illnesses present as depression, so both are looked for.
The likely interaction of the needed psychiatric treatment with the ongoing medical treatment is part of the formulation.
A symptom thought to be functional still needs evaluation for organic causes before that conclusion.

Test yourself

Think of the answer, then tap the question to see it.

What is the difference between consultation and liaison?

Consultation answers a specific question about one patient; liaison is ongoing work with a team to improve care and train staff.

What is the most common reason for hospital psychiatric referral?

Delirium, in published series; it is often overlooked or mislabelled as depression or psychosis.

A surgical patient refuses an operation and the team asks for a psychiatric consultation. What is the real question?

Whether the patient has decision-making capacity: when someone declines recommended treatment, capacity becomes an essential consideration.

A hospital patient becomes agitated and the team calls it psychosis. What should be looked for first?

Delirium: its hyperactive form is often mistaken for psychosis.

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Educational content on behavior and the clinical relationship; not a diagnostic or treatment guide and no substitute for assessment by a health professional. If you or someone near you is at risk, seek help now from an emergency service or a mental-health helpline.

Sources: Assessment of Psychiatric Disorders in Consultation-Liaison Setting (Indian Journal of Psychiatry, PubMed Central, 2022); Medical Assessment of the Patient With Psychiatric Symptoms (MSD Manual Professional Edition, 2024); Delirium (MSD Manual Professional Edition, 2025); A pragmatist’s guide to the assessment of decision-making capacity (British Journal of Psychiatry, PubMed Central, 2019).

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