BACKGROUND: This study describes evidence of yoga's effectiveness for depressive disorders, general anxiety disorder (GAD), panic disorder (PD), and posttraumatic stress disorder (PTSD) in adults. We also address adverse events associated with yoga. METHODS: We searched multiple electronic databases for systematic reviews (SRs) published between 2008 and July 2014, randomized controlled trials (RCTs) not identified in eligible SRs, and ongoing RCTs registered with ClincalTrials.gov. RESULTS: We identified 1 SR on depression, 1 for adverse events, and 3 addressing multiple conditions. The high-quality depression SR included 12 RCTs (n = 619) that showed improved short-term depressive symptoms (standardized mean difference, -0.69, 95% confidence interval, -0.99 to -0.39), but there was substantial variability (I2 = 86%) and a high risk of bias for 9 studies. Three SRs addressing multiple conditions identified 4 nonrandomized studies (n = 174) for GAD/PD and 1 RCT (n = 8) and 2 nonrandomized studies (n = 22) for PTSD. We separately found 1 RCT (n = 13) for GAD and 2 RCTs (n = 102) for PTSD. Collectively, these studies were inconclusive for the effectiveness of yoga in treating GAD/PD and PTSD. The high-quality SR for adverse events included 37 primary reports (n = 76) in which inversion postures were most often implicated. We found 5 ongoing trials (3 for PTSD). CONCLUSIONS: Yoga may improve short-term depressive symptoms, but evidence for GAD, PD, and PTSD remain inconclusive.