Background: Recent studies cast doubt on the net effect of antipsychotics for delirium.

Aim: To investigate the influence of these studies and other factors on clinicians' delirium treatment practice and practice change in palliative care and other specialties using the Theoretical Domains Framework.

Design: Australia-wide online survey of relevant clinicians. SETTING/

Participants: Registered nurses (72%), doctors (16%), nurse practitioners (6%) and pharmacists (5%) who cared for patients with delirium in diverse settings, recruited through health professionals' organisations.

Results: Most of the sample (n = 475): worked in geriatrics/aged (31%) or palliative care (30%); in hospitals (64%); and saw a new patient with delirium at least weekly (61%). More (59%) reported delirium practice change since 2016, mostly by increased non-pharmacological interventions (53%). Fifty-five percent reported current antipsychotic use for delirium, primarily for patient distress (79%) and unsafe behaviour (67%). Common Theoretical Domains Framework categories of influences on respondents' delirium practice were: emotion (54%); knowledge (53%) and physical (43%) and social (21%) opportunities. Palliative care respondents more often reported: awareness of any named key study of antipsychotics for delirium (73% vs 39%, p < 0.001); changed delirium treatment (73% vs 53%, p = 0.017); decreased pharmacological interventions (60% vs 15%, p < 0.001); off-label medication use (86% vs 51%, p < 0.001: antipsychotics 79% vs 44%, p < 0.001; benzodiazepines 61% vs 26%, p < 0.001) and emotion as an influence (82% vs 39%, p < 0.001).

Conclusion: Clinicians' use of antipsychotic during delirium remains common and is primarily motivated by distress and safety concerns for the patient and others nearby. Supporting clinicians to achieve evidence-based delirium practice requires further work.