The long-term goal of this research program is to define the alterations in brain chemistry that underlie MA use disorders, and to utilize translational magnetic resonance spectroscopy (MRS) neuroimaging to identify rational brain-based treatment targets. Once a hypothesis-driven intervention is identified, MRS can then be further employed in treatment studies, to verify that "target engagement" is achieved. The specific aims of this proposal are an example of this stepwise scientific process: the nutritional supplement creatine will be tested in a randomized, placebo-controlled study of women with MA use disorders, to investigate creatine's effect on cerebral PCr levels, depressive symptoms, and MA usage.