Data source and key concepts

National Non-Admitted Patient Emergency Department Care Database

All state and territory health authorities collect a core set of nationally comparable information on emergency department (ED) presentations (including mental health-related ED presentations) in public hospitals within their jurisdiction. The AIHW compiles this data annually to form the National Non-Admitted Patient Emergency Department Care Database (NNAPEDCD). In 2020–21, 291 of Australia’s public hospital emergency departments reported emergency department presentations to the NNAPEDCD (AIHW 2022b).

Prior to 2014–15, diagnosis-related information was not included in the NNAPEDCD and states and territories provided the AIHW with a bespoke analysis of mental health-related emergency department presentations. Diagnosis-related data has subsequently been included in the NNAPEDCD. In this report, data from 2014–15 to 2020–21 are sourced from the NNAPEDCD.

Definition of mental health-related emergency department presentations

Mental health-related ED presentations in this report are defined as presentations in public hospital EDs that have a principal diagnosis of Mental and behavioural disorders (that is, codes F00–F99) in ICD-10-AM or the equivalent codes in ICD-9-CM. It does not include codes for self-harm or poisoning.

The Mental and behavioural disorders principal diagnosis codes may not fully capture all mental health-related presentations to EDs, such as presentations for self-harm. Diagnosis codes for intentional self-harm sit outside the Mental and behavioural disorders chapter (X60–X84). Additionally, a presentation for self-harm may have a principal diagnosis relating to the injury, for example Open wound to wrist and hand. These presentations cannot be identified as mental health-related presentations in the NNAPEDCD and are not included in this report.  

Further information on the NNAPEDCD is available on METeOR, the AIHW’s Metadata Online Registry.

Presentation of regional data

Please refer to the technical notes for information on how data at regional levels are reported.

Mental health-related services in emergency departments key concepts
Key concept Description

Emergency department (ED) presentation

Emergency department (ED) presentation refers to the period of treatment or care between when a patient presents at an ED and when that person is recorded as having physically departed the ED. It includes presentations for patients who do not wait for treatment once registered or triaged in the ED, those who are dead on arrival, and those who are subsequently admitted to hospital or to beds or units in the ED. An individual may have multiple presentations in a year. For further information can be found in the  Non-admitted emergency department care NMDS 2020–21

Episode end status The episode end status indicates the status of the patient at the end of the non-admitted patient emergency department service episode. Further details on episode end status codes are available from the AIHW AIHW the Metadata Online Registry (METEOR)

Mental health‑related emergency department (ED) presentation refers to an emergency department presentation that has a principal diagnosis that falls within the Mental and behavioural disorders chapter (Chapter 5) of ICD‑10‑AM (codes F00–F99). It should be noted that this definition does not encompass all mental health‑related presentations to emergency departments, as detailed above. Additional information about this and applicable caveats can be found in the data source section.

Primary Health Network (PHN)

A Primary Health Network is an administrative health region established to deliver access to primary care services for patients, as well as co-ordinate with local hospitals in order to improve the overall operational efficiency of the network.  Further details on PHNs are available from the Australian Government Department of Health.

Principal diagnosis

The principal diagnosis is the diagnosis established at the conclusion of the patient’s attendance in an emergency department to be mainly responsible for occasioning the attendance.

Socio-Economic Indexes for Areas (SEIFA)

SEIFA is a product developed by the Australian Bureau of Statistics (ABS) that ranks areas in Australia according to relative socio-economic advantage and disadvantage. It consists of 4 indexes based on information from the five-yearly Census of Population and Housing, each being a summary of a different subset of Census variables and focuses on a different aspect of socio-economic advantage and disadvantage. Further details are available from the ABS.

Statistical Area 3 (SA3)

SA3s create a standard framework for the analysis of ABS data at the regional level through clustering larger geographic groups that have similar regional characteristics, administrative boundaries or labour markets. SA3s generally have populations between 30,000 and 130,000 persons. In regional areas, SA3s represent the area serviced by regional cities that have a population over 20,000 people. In the major cities, SA3s represent the area serviced by a major transport and commercial hub.


The triage category indicates the urgency of the patient’s need for medical and nursing care. It is usually assigned by an experienced registered nurse or medical practitioner at, or shortly after, the time of presentation to the emergency department. The triage category assigned is in response to the question: ‘This patient should wait for medical assessment and treatment no longer than...?’

The Australasian Triage Scale has 5 categories that incorporate the time by which the patient should receive care:

  • Resuscitation: immediate (within seconds)
  • Emergency: within 10 minutes
  • Urgent: within 30 minutes
  • Semi-urgent: within 60 minutes
  • Non-urgent: within 120 minutes.