Stress Management in Depressive Disorder: Resilience Training vs. Yoga: Biological, Epigenetic, and Brain Correlates

Stress perception and stress processing modes in the sense of state characteristics will be assessed with the Stress Processing Questionnaire (SVF-ak) (Janke & Erdmann, 1997; Janke et al., 1985; Kühn, 1986). The SVF-ak retrospectively asks about the stress processing methods used during a previous stress phase/period. The short version of this instrument which will be used in this study consists of 42 questions for the assessment of the extent to which the 19 processing strategies of the SVF - supplemented by the subtest helplessness - were used in certain stressful situations. Subjects indicate on a 4-point scale ranging from 0 (in no case) to 3 (for sure/ with certainty), how often the thought formulated in the item "went through their mind in the previous situation".

The German version of the Perceived Stress Scale (PSS-10) by Klein et al. (2016) will be used to measure excessive demands and the perception of stress. Subjects indicate on a 5-point Likert scale ranging from null (never) to four (very often) the extent to which situations in their own lives were unpredictable, uncontrollable, and overwhelming in the past month.

Assessment of present and long-lasting anxiety levels will be carried out with the State-Trait-Anxiety Inventory (STAI) (Spielberger et al., 1970, German version by Laux et al., 1981). This is a widely used 40-items multiple-choice questionnaire assessing two dimensions of anxiety: anxiety as a trait (STAI-T), and anxiety as a transient emotional state (STAI-S). The STAI comprises 20 anxiety-related items rated on a 4-point Likert-scale ranging from 1 (not at all) to 4 (totally). Total scores range from 20 to 80 with higher scores indicating higher anxiety. Both state and trait anxiety will be assessed at baseline. At the other time points (mid, post1, post2) only state anxiety will be assessed.

Resilience will be evaluated using the Resilience Scale for Adults (RSA; Friborg, 2003; German version by Kaiser et al., 2019). This scale consists of 33 items rated on a 7-point intensity response scale and is used to measure both intra- and interpersonal protective factors. These protective factors promote adaptation to adversity and are examined in the following areas: self-perception, future planning, social competence, structural style, family cohesion, and social resources. Mean scores within each subscale are calculated or the total score.

Subjectively perceived quality of life will be assessed with the WHO Quality of Life - Brief Version quality of life measure (WHOQOL-BREF; Skevington et al., 2004). This is a 26-item self-report questionnaire to assess quality of life over the past two weeks in four domains: physical, psychological, social, and environmental. The items are rated on a five-point Likert scale from 1 (absent) to 5 (severe). The total scale is used in this study with higher scores indicating better quality of life.

The primary outcome - severity of depressive symptoms will be evaluated by means of the Beck Depression Inventory-II (BDI-II) (Beck et al., 1996; German translation by Kühner et al., 2007). The BDI-II is a 21-item self-report questionnaire to assess the severity of depression in the past two weeks. Each question has a set of four possible responses, ranging in intensity and resulting in a maximum total score of 63. Higher total scores indicate more severe depressive symptoms. BDI scores between 0 and 13 indicate absent to minimal depressive symptoms, from 14 to 19 mild symptoms, from 20 to 28 moderate symptoms, and from 29 to 63 severe depressive symptoms.

The severity of (residual) depressive symptoms will be evaluated using the MADRS. This observer-rated interview consists of 10 items (apparent sadness, reported sadness, internal tension, decreased sleep, decreased appetite, difficulty concentrating, fatigue, inability to feel, as well as pessimistic and suicidal thoughts), with each item scoring from 0 to 6. The total score ranges from 0 to 60 with higher scores reflecting a higher severity of symptoms. MADRS score ranging from 0 to 6 indicates absent to minimal depressive symptoms, from 7 to 19 mild depression, from 20 to 34 moderate depression, score of 35 and greater indicates severe symptoms and score of 60 indicates very severe depression.

Alcohol/ tobacco consumption will be assessed using the Tobacco and Alcohol Questionnaire (Sánchez-Gutiérrez et al., 2023)

The degree of engagement, immediate response, and changes in affective state will be monitored before and after the first, fifth, and tenth training unit using the Positive and Negative Affect Schedule (PANAS) (German version by Breyer & Bluemke, 2016). This questionnaire consists of 20 adjectives that describe various feelings and emotions and are rated on a five-point scale from "not at all" to "very much". Ten adjectives each capture the dimensions of positive and negative affect. The result is the sum of the values.