Sleep-related eating disorder (SRED) is classified within parasomnia and is characterised by recurrent episodes of abnormal, dysfunctional eating during sleep. This report describes a case of SRED in a 19-year-old woman admitted to the psychiatric ward with worsening anxiety, low mood and suicidal ideation. She was started on low-dose mirtazapine for mood stabilisation and, following an incremental increase to 30 mg, she developed nocturnal binge eating of which she retained only partial memory on waking. She developed adverse health consequences as a result of these recurrent episodes. The subject's symptoms were relieved rapidly following reduction of the dose of mirtazapine back to 15 mg.