OBJECTIVE: To examine the effects of Hatha yoga therapy on resilience, brain-derived neurotrophic factor (BDNF) levels, and salivary alpha amylase (SAA) activity in patients with schizophrenia-spectrum disorders. DESIGN AND PARTICIPANTS: Single-blinded, randomized controlled study in which outpatients with schizophrenia or related psychotic disorders (according to International Classification of Diseases, 10th Revision) were randomly assigned to a yoga or a control group. SETTING: November 2012-April 2013 at Yamanashi Prefectural Kita Hospital, Japan. INTERVENTIONS: In the yoga group, patients received weekly 1-hour Hatha yoga sessions, in addition to regular treatment, for 8 weeks. Those in the control group underwent regular treatment, which included a daycare rehabilitation program. OUTCOME MEASURES: Assessments included the 25-item Resilience Scale (RS), Positive and Negative Syndrome Scale (PANSS), plasma and salivary BDNF level, and SAA activity. RESULTS: Fifty patients participated (25 in each group; mean age+/-standard deviation, 50.9+/-11.3 years; mean duration of illness, 25.0+/-10.3 years; mean total PANSS score, 78.2+/-17.3). No significant differences in changes in any variable from baseline to week 8 were found between the two groups (changes in the yoga group versus the control group: RS score, -1.6+/-19.9 versus 0.3+/-17.2; PANSS score, 0.5+/-12.0 versus 5.0+/-15.6; plasma BDNF, 41.6+/-377.0 pg/dl versus 73.4+/-346.0 pg/dl; SAA, -26.2+/-72.6 kU/l versus -13.8+/-68.0 kU/l, respectively). CONCLUSIONS: Adjunct yoga therapy showed no positive changes in resilience level or stress markers. Duration and intensity of yoga sessions and the focus on patients with chronic illness may explain the negative observations in light of past positive evidence regarding yoga therapy.