It is estimated that 1 in 4 people in a year will have some kind of mental health problem, and that mixed anxiety and depression is the most common disorder in the UK. There is an increasing number of mental health patients attending the ED, and a new FY doctor in the ED will encounter such patients from their first shift onwards. The approach to a mental health patient is only marginally different from the approach to those presenting under other specialties. The assessment largely depends on careful history taking and attentively listening to the patient’s narrative. There are only a few situations in psychiatry in which a physical examination and investigations are required in the ED to make a diagnosis. As it would not be possible to cover all the areas of psychiatry which come through the doors of the ED in one chapter, only a few questions have been included here to provide a flavour of the common psychiatric situations that FY1/2s may come across in their early training period. The UK has the highest rate of self-harm in Europe and so one of the most important points is to recognize suicidal patients who can harm themselves seriously and manage them appropriately. If such patients are discharged following an inadequate assessment, they may go on to commit suicide and the attending doctors would have missed the opportunity to support and save them. In this category of patients, when they present to the ED, no matter how minimal is the level of their self-mutilation, it is a serious ‘cry’ for help. Our job is to listen to the patient and support them with the maximum help we can provide. As it may be difficult to occasionally get to the bottom of the problem, particularly within the time constraints in the ED, a low level of suspicion should be kept to ask for the assistance of the mental health expert. Self-harm and depression go almost hand in hand. The suicidal rate is higher in depressed patients than in the general population.