Psychotic depression is a severe and underdiagnosed psychiatric disorder, which differs from non-psychotic depression biologically, clinically, therapeutically and prognostically. Due to the differences in treatment and the higher risk of suicidal behaviour, the correct diagnosis is crucial. Patients with psychotic depression have an increased risk of a new episode and readmission. Treatment of psychotic depression takes place during hospitalisation and is either ECT or a combination of antidepressant treatment and antipsychotics, which is summarised in this review.