Creatine for Depressed Male and Female Methamphetamine Users

This trial is testing whether the nutritional supplement creatine can help reduce depression and anxiety symptoms in people who use methamphetamine (crystal meth) and have been diagnosed with depression and anxiety. **You may be eligible if...** - You currently use methamphetamine as your primary substance of use - You have been diagnosed with major depressive disorder (whether caused by methamphetamine or independent of it) - You also have a diagnosis of an anxiety disorder - Your depression score (Hamilton Depression Rating Scale) is 16 or higher - Your anxiety score (Hamilton Anxiety Scale) is 18 or higher - If you are on a psychiatric medication, your dose has been stable for at least 4 weeks **You may NOT be eligible if...** - You are unable to give informed consent - You are at significant risk of suicide or harming others - Your primary substance use disorder is something other than methamphetamine - You are pregnant (if female) - You have a history of kidney disease - You have a significant medical or neurological illness - You have had a previous allergic reaction to creatine Talk to your doctor to see if this trial is right for you.