Methods
This research adhered to ethical research standards and was approved by the UCLA Institutional Review Board.
Participants were recruited by flyers on campus bulletin boards, newspaper advertisements and internet notices, and letters to UCLA clinical faculty. Thirty-seven people qualified for the study after telephone screening and intake diagnostic interview, 27 women and 10 men; 33 White, 1 African, and 3 Asian-American; mean (range), age 44.8 (20-71); years of education 16.8;[12,13,14,15,16,17,18,19,20,21] BMI 26.7;[20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55] hours of exercise/week 5.4 (0-30); alcohol drinks/week 1.3 (0-8); 6 students, 3 retirees, 2 unemployed, 26 in professional, technical and white collar occupations.
Based on history and intake diagnostic interview (Mini-International Neuropsychiatric Interview),[39] all participants were diagnosed with unipolar major depression in partial remission; partial remission was operationalized as having self-reported improvement in depression severity with pharmacotherapy, but with residual symptoms reflected by scores on the 17-item Hamilton Depression Scale (HAM-D) of 7-18. Participants had to be under the care of a physician and taking anti-depressant medication for at least 3 months, which continued during the study. The average Hamilton-D17 (HAM-D) score at intake was 12.5;[7,8,9,10,11,12,13,14,15,16,17,18] number of depressive episodes 2.8;[1,2,3,4,5,6] months on medication 75.6 (3-336). Participants were excluded (i) for Axis I diagnoses of bipolar disorders, delirium or dementia, schizophrenia or other psychotic disorders, or current substance-related or eating disorders; (ii) for any medical illness or other conditions that would pose a safety concern or limit participation; (iii) for suicidal thoughts or tendencies. Medication type was as follows: selective serotonin reuptake inhibitor (SSRI) (n = 15); serotonin-norepinephrine reuptake inhibitor (SNRI) (n = 4); Dopaminergic (n = 4); augmented/combination drug regimen (n = 14). Medication category was unrelated to treatment outcome after the yoga intervention. Individuals with >3 months of prior yoga experience were excluded. The protocol was approved by the UCLA Institutional Review Board, and informed consent was obtained from all participants. Approval for participation in the study was obtained from each participant's own treating physician.
Out of the 37 people who qualified for the study and completed the intake procedures, six did not attend any classes, six attended one class, two attended two classes, one attended three classes and one attended five classes. None of these 16 participated in the final assessment and few responded to telephone inquiries. Based on some limited feedback from these people and informal observations of research assistants, the issues were difficult in making a commitment in general, conflicts with other activities, various inconveniences or concern about the physical demands. The remaining 21 attended six or more sessions, which we estimated would be likely to have an effect. These 21 are labeled 'Ins' and the other 16 'Outs'. The 16 Outs included 12 women and 4 men; the 21 Ins included 15 women and 6 men.
Of the 21 Ins, four (19%) did not return for the final assessment or respond to telephone calls. These four dropouts (all women) attended 10, 12, 12 and 17 sessions. The remaining 17 are labeled Completers (11 women, 6 men). Thus, the primary participants were the 17 who attended six or more sessions and who completed both intake and post-intervention assessments.
Eleven participants (65%) ended the study at remission levels (REMISS, <7 on HAM-D); for the remaining six participants (Non-Remiss), one showed a sizable reduction (14-9) and the other five small changes. The REMISS group contained six women and five men; the NON-REMISS group contained five women and one man.
Yoga instruction was provided in three groups of 12-13 participants over an 8-week period, three sessions a week with a total of 20 sessions per group because of holidays and incidental cancellations. The 60-90 min classes were led by three highly experienced certified Iyengar yoga teachers who rotated over the sessions. The three groups did not differ in attendance rates or in the HAM-D or Quick Inventory of Depressive Symptoms (QIDS) scores. Yoga instruction followed sequences of yoga asanas, specifically designed by the teachers for this study to improve mood and alleviate depression, based on the writing and teaching of BKS Iyengar[11,12] and other leaders in the field.[40,41] There were three classes every week. One of the classes focused on inverted poses such as Salamba Sarvangasana (shoulderstand) and Viparita Karani (supported inversion with bolsters and wall). The poses were introduced in stages in a progressive manner week by week according to the ability of the students. The inversion sequence eventually incorporated poses such as Adho Mukha Vrksasana (Handstand) and Sirsasana (headstand). A second class each week focused on backbends which emphasized the expansive chest opening aspects of back arching asanas in both supported (with chairs, bolsters, block, etc.) and unsupported versions. The third class every week focused on restorative poses using props in a specific manner to support the student in backbends, inversions and supine poses in order to be able to hold the poses longer and cultivate the relaxing benefits in the pose in addition to the other properties in the pose that help elevate mood. As in the aforementioned inversion sequence, the back bending and restorative sequences were also taught in a progressive manner. The yoga teachers were not given any information about the participants' individual characteristics or research data. A complete list of the asanas may be obtained on request.
Psychological Measures. The intake and post-intervention assessment consisted of a diagnostic interview and health history, demographic questionnaire and the following personality tests: 17-item HAM-D, QIDS, SCL, Spielberger Anger Expression Scale providing indices of Anger In (suppression of anger, ANGIN) and Anger Out (expression of anger, ANGOUT), Spielberger Trait Anxiety Inventory (STAI), Cook-Medley Hostility Scale (indirect hostility), Pittsburgh Sleep Scale (SLEEP), and the SF-36 short-form health survey, which includes eight dimensions related to physical and emotional limitations on functioning, bodily pain, general mental health, vitality, general health, limitations in usual role activities related to physical and to emotional problems. As significant effects were found only for the last dimension on emotional limitations in role activities (RESF36), for simplicity data for the other SF-36 dimensions will not be presented. The primary outcome measure of therapeutic effect was the change in HAM-D score from intake to post-intervention.
The electrocardiogram and continuous BP (Finapres) were measured for 20 min in a soundproof laboratory under resting conditions with no other tasks or stimulation. Aside from measures of HR and BP, the HR variances of residual time series (the filtered waveforms) after a band-pass optimal FIR (finite impulse response) filtering for alien frequencies and baseline trend were used to calculate HR variability (HRV, ms2) in two frequency bands: low frequency (LF-HRV, 0.075-0.125 Hz) and high frequency (HF-HRV, 0.125-0.50 Hz); LF-HRV measures both sympathetic (SNS) and parasympathetic (PNS) and HF-HRV measures PNS influences on the heart. The specific indices were the log-transformed variance of HF-HRV and LF-HRV, ratio of the log-transformed variance of LF-HRV to the sum of the logs of the two bands (LFTOT-HRV), ratio of log-transformed variance of HF-HRV to the sum of the logs of the two bands (HFTOT-HRV) and ratio of log-transformed variance of LF-HRV to log-transformed HF-HRV (LFHF-HRV).
A measure of BRS was obtained by the Sequence Method developed by Andrew Steptoe.[42] BRS indicates how the ANS adapts to fast changes in BP by measuring the slope of the change in the cardiac interbeat interval to a successive increase or decrease in BP over a minimum of three beats. For further details of the physiological recording and data processing methods see reference.[30]
Participants were asked to rate their moods before and after each class from 1 = not at all to 5 = very much for each of the 20 mood items. The moods were selected to tap three dimensions of affective state: positive (happy, relaxed, optimistic, confident, content), negative (stressed, sad, frustrated, irritated, depressed, anxious, blue, angry, pessimistic) and energy-arousal (attentive, fatigued, alert, tired, energetic, sleepy).[43]
Systat (v. 10) was used to analyze the data using within- and between-group t-tests and general linear models (GLM). An example of the latter is the analysis of the effects of an independent variable, such as whether participants achieved remission levels or not versus the repeated measure of change in HAM-D scores from pre- to post-intervention. Random regression models (SAS, Proc Mixed) were used to analyze the longitudinal mood ratings obtained over the course of the yoga sessions. These models consider both within- and between-subject variability, and allow for random and fixed effects (mixed modeling) as well as a variable number of observations per subject and missing data, such as missed sessions.
Evid Based Complement Alternat Med. 2007;4(4):493-502. © 2007 Oxford University Press
Cite this: Yoga as a Complementary Treatment of Depression: Effects of Traits and Moods on Treatment Outcome - Medscape - Dec 01, 2007.
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