NDST consists in a form of therapeutic intervention from which all intervention principles pertaining to specific psychotherapeutic protocols are removed while maintaining the so-called common factors from different psychotherapy approaches. In other words, it is an unstructured therapy without specific psychological techniques other than those belonging to the basic interpersonal skills of the therapist, such as reflection, empathic listening, encouragement, and helping people to explore and express their experiences and emotions.

The CGI provides an overall clinician-determined summary measure that takes into account all available information, including a knowledge of the patient's history, psychosocial circumstances, symptoms, behavior, and the impact of the symptoms on the patient's ability to function.The CGI actually comprises two companion one-item measures evaluating the following: (a) severity of psychopathology from 1 to 7 and (b) change from the initiation of treatment on a similar seven-point scale (Busner & Targum, 2007). Higher scores indicate higher severity of symptoms or worse evolution.

The WHOQOL-BREF is a 26-item questionnaire which includes one item from each of the 24 facets contained in the WHOQOL-100 and two additional items on overall quality of life and general health. The 24 items are organized into 4 domains, namely Physical Health, Psychological, Social Relationships and Environment. In this study we analysed only the fis=rst three domains, because environment characteristics was not supposed to change with psychological interventions. The internal consistencies for WHOQOL were .77, .77, and .81 for the psychological subscale, .78, .76, and .82, for the physical subscale, and .72, .64, and .73 for the social subscale across pretreatment, posttreatment, and 3 month follow up. Higher scores indicate higher quality of Life. Scores of physical, psychological and social domains range from 7 to 35; 6 to 30 and 3 to 15.

It is a discretized analog disability scale (DISS) which uses visual-spatial, numeric and verbal descriptive anchors to assess disability across three domains: work, social life and family life. The internal consistencies for the Sheehan were .71, .80, and .91 across pretreatment, posttreatment, and 3 month follow up. Higher scores indicate higher disability. Scores range from 1 to 10 for each domain.

The Acceptance and Action Questionnaire (AAQ-II-7: Bond, 2011; Flederus, 2012) is a 7-item uni-dimensional measure that assesses experiential avoidance: the unwillingness to remain in contact with aversive private experience and behaviors aimed at altering these experiences or the events that elicit them. Items are scored on a 7-point likert scale ranging from 1 (never true) to 7 (always true). Higher scores indicate higher levels of experiential avoidance and lower levels of psychological flexibility

The 39-items Five Facets of Mindfulness Questionnaire (FFMQ; Baer et. al., 2006, adapted for Brazil by Barros, 2014), was used for measuring mindfulness in a multidimensional manner for a factorial analysis of different elements of the construct, divided in five domains (i.e. observing, describing, acting with awareness, non-judging of inner experience, and non-reactivity to inner experience). Items are scored on a 5-point likert scale ranging from 1 (never or very rarely true) to 5 (very often or always true). Higher scores indicate higher levels of mindfulness.

The Credibility and Expectancy Questionnaire (CEQ; Borkovec & Nau, 1972; Devilly & Borkovec, 2000) is a 6-item self-report instrument that measures treatment credibility and client expectancy for improvement. The first four items of this scale (set I) are rated based on cognitive appraisal whereas the last two items (set II) are rated based on feelings about the therapy. One item of each set is scored as porcentage (0 to 100) and all of the other items are scored on a 9-point likert scale ranging from 1 (nota t all) to 9 (very). Higher scores indicate higher levels of credibility (first 3 items) and expectancy (last 3 items).

The MHC-SH (Keyes, 2009 - adapted to Brazilian population by Machado and Bandeira, 2015 ) is a 14-item self-responding instrument that measures positive mental health, witch is understood as symptoms of good affection, self development and social connectivity. Items are scored on a 6-point likert scale ranging from 1 (never) to 6 (every day). The score ranges from 14 to 84. Higher scores indicate higher levels of mental health.

Blood samples were collected before and after psychological interventions. High sensitivity CRP, expressed in mg/L, was measured using immunoturbidimetric method. High scores indicate cardiovascular risk and/or presence of infectious or inflammatory processes.

Blood samples were collected before and after psychological interventions. Serum levels of IL-1beta, IL-4, IL-6, IL-8, IL-10, TNFalpha and Vascular Endothelial Growth Factor (VEGF), all expressed in pg/mL, were quantified simultaneously using Luminex xMAP technology with a commercial multiplex immunoassay kit according to the manufacturer's instruction.

Blood samples were collected before and after psychological intervention. Plasma levels of BDNF were measured using an enzyme-linked immunosorbent assay (ELISA).

Blood samples were collected before and after psychological intervention. Plasma levels of serotonin were measured using an enzyme-linked immunosorbent assay (ELISA).

The TCI-R is a self-reported questionnaire, with 240 questions that require answers in a 5-point-Likert scale. Each question is related to one of the seven factors described by the authors of the scale: novelty seeking, harm avoidance, reward dependence, persistence, self-directedness, cooperativeness and self-transcendence.