Research has examined the effects of micronutrients on mood in both healthy and psychiatric populations. EMPowerplus (EMP+) is a formula containing a wide range of vitamins and minerals. It has been examined for the treatment of mood instability, anxiety, Attention Deficit Hyperactivity Disorder (ADHD) and autism. The present study trialled EMP+ with five adolescents, aged 16-21, all with Severe Mood Dysregulation (SMD) as well as co-occuring psychiatric diagnoses i.e. ADHD, anxiety and substance abuse. The sample reflects a group of adolescents with complex psychiatric presentations and therefore difficult to treat. An ABAB (off-on-off-on) research design was employed. An open-label trial (8 weeks) of the micronutrients was followed by a withdrawal phase (8 weeks) and then a reinstatement of the micronutrients for a longer period of time (up to 24 weeks). There were in-depth pre and post assessments and on-going monitoring of the participants for the duration of the study. Clinically significant improvements in symptoms and functioning were demonstrated in three/four participants. Two participants demonstrated on-off control of psychiatric symptoms, with a reversal and replication of treatment effect. Further, one participant demonstrated clinically significant improvements in mood and functioning while on the micronutrients; however, he was lost to follow up following the 7.1 earthquake, and a reversal was not obtained. One participant demonstrated a trend toward improvements in mood while on the micronutrients and subsequent deterioration during the wash-out phase. However, she decided to withdraw from the study at four weeks off to go on psychiatric medication. Further, one participant demonstrated a variable response. This study provides some further evidence that micronutrients may be an effective treatment for psychiatric symptoms, consistent with other reports. Further research, such as randomised clinical trials and studies investigating the mechanisms of action, appears warranted.