a true control would be something with a similar placebo effectIt does . So Group 1 was assigned to SKY while Group 2 was put in the waiting list , then Group 2 was assigned to another form of yoga when Group 1 was completed . That means you can compare Group 1 to a baseline controlnothing , as well as comparing Group 1 SKY treatment to Group 2 normal yoga treatment . if I ' m reading it rightthis study has very small numbers as wellThis makes some sense because their registration had extremely specific inclusion and exclusion criteria . Inclusion Criteria DSMIV Major Depressive Disorder Able to give informed consent Aged 1867 Currently in outpatient care for MDD On a stable antidepressant regimen for at least 2 months 17 item Hamilton Depression Score 14 at screening baseline visitExclusion Criteria Currently in crisis requiring inpatient treatment Bipolar Disorder , Psychotic Disorder , ADHD , Substance Use Disorder Pregnancy , Epilepsy Initiating psychotherapy or other yogameditation program