 The multi-centre RCT will determine the safety and efficacy of IM olanzapine, in comparison with conventional medicines haloperidol or midazolam in a three-arm comparison for the sedation of acutely agitated patients in AEDs. Specifically, we aim to determine if administration of IM olanzapine ais more effective than sedation with IM haloperidol or IM midazolam alone; bis safer than sedation with comparison arms; cdecreases the amount of subsequent redosing or alternative drugs required; dis more favourable than the haloperidol and midazolam arms with respect to safety, efficacy and adverse events. 