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Down the Rabbit Hole
Paul Kiritsis, PsyD Clinical Psychology, DPhil., MA (History)


The Therapeutic Efficacy of Mindfulness-Based Stress Reduction (MBSR)

Paul Kiritsis - Tuesday, February 24, 2015

            In the last twenty years there has been a swift increase in the publication of clinical studies about alternative and complementary treatments to conventional medicine like mindfulness-based interventions and their efficacy in contending with a whole continuum of psychological conditions from anxiety and depression to more organic variants like stress-related somatic symptoms (Baer, 2003; Hayes, Strosahl, & Wilson, 1999; Salsman & Linehen, 2006). One of the most common types is Mindfulness Meditation (MM), which has been defined as the process of “bringing one’s complete attention to the present experience on a moment to moment basis (Marlatt & Kristeller, 1999)” as well as “paying attention in a particular way: on purpose, in the present moment, and nonjudgmentally (Kabat-Zinn, 1994).”

        Meditation can be understood as the intentional focusing of attention to internal or external phenomena for the purpose of acquiring a sense of peaceful repose. Mindfulness, on the other hand, is the detached, impartial observation of sensation, thought, feeling, proprioception, and what not that might drift in and out of conscious awareness from moment to moment. Together they suspend the habitual patterns of the mind and its tendencies to cogitate about past and future, amplifying awareness of the present moment. More importantly they foster a ‘stillness’ through which increments in self-awareness, self-compassion, and insight may be cultivated. Because this ability doesn’t come naturally to human beings, researchers subjecting their experimental groups to MM will frequently evoke segues with animate imagery such as insignificant events at a train station or vicissitudes in the morphology of the heavens (Baer, 2003). The degree of decentering and detachment experienced during MM has led some researchers to label the entire process ‘metacognitive insight’ (Teasdale, 1999). Experimental studies have found that sustained MM practice both breaks down regimented cognitive schemas so that they become more adaptive and flexible in nature and promotes constructive experiences in objectivity, acceptance, and meta-cognition (Baer, 2003; Brown & Ryan, 2003; Hayes & Kelly, 2003). Deploying such practices in one’s day-to-day routine should expedite mind-brain-body balance and health along with heightened, improved, or deeper feelings of wellbeing, or so the rationale underlying these momentous research finds inform us.

        In 2000, Speca, Carlson, Goodey, & Angen recoursed to a randomized, wait-list controlled clinical trial for the sake of examining the effects of MM on the mood disturbances and perceived stress of cancer patients. The experimenters recruited a heterogeneous group of ninety subjects–23 males and 74 females–suffering from multifarious cancer types before assigning them to treatment and wait-list control groups. All participants completed pre- and post-questionnaires, including the Profile of Mood States (PMS) and the Symptoms of Stress Inventory (SSI). The principal intervention consisted of active participation in a 1.5 hour meditation group along with home meditation practice for seven consecutive weeks (Speca et al., 2000). It was ascertained that patients in the treatment group scored significantly lower on total mood disturbances and subscales of depression, anxiety, anger, and confusion than subjects in the control group. Moreover, cardiopulmonary and gastrointestinal symptomology, emotional irritability, depression, and cognitive disorganization were significantly reduced in the experimental group. In retrospect, these results support the contention that an MM program effectively reduces mood disturbances, fatigue, and a broad spectrum of stress-related symptoms in a heterogeneous group of patients suffering from variant forms of cancer (Speca et al., 2000).  

        A year afterward the effects of MM intervention were examined in a heterogeneous group of 136 male and female patients with ages ranged between 23 to 76 (Reibel, Greenson, Brainard, & Rosenzweig, 2001). The intervention strategy involved eight consecutive weeks of practicing twenty minutes of meditation daily. Three health-related questionnaires, the Medical Outcomes Study Short-Health Survey (SF-36), the Symptom Checklist-90 Revised (SCL-90-R), and the medical Symptom Checklist (MSCL), were used to assess current status for psychological and somatic health. Body tension, mental clarity, and subjective feelings of wellbeing were assessed immediately before and after each weekly session using 10-point Likert-scale ratings in conjunction with pre- and post-course health surveys. Indices of the SF-36 quantifying vitality, somatic pain, role limitations instigated by poor heath, and social functioning demonstrated that subjective appraisals pertaining to quality of life improved exponentially post-intervention (P<.01). Most compatible with this was a mitigation of physical symptoms as indicated by the MSCL and a reduction of psychological distress (P<.0001) on the Global Severity Index (38%), the anxiety subscale (44%), and the depression subscale (34%) as indicated by the SCL-90-R. Using the results as a guide, experimenters deduced that MM training programs encompassed long-term beneficial effects for functional status, psychological distress, and somatic symptomology in a heterogeneous patient population (Reibel et al., 2001).    

        More recently, Mackenzie, Carlson, Munoz, & Speca (2007) utilized a purely qualitative research design to explore the self-perceived effects of MM on nine subjects suffering from cancer. Prerequisites for selection into the study included completion of an introductory 8-week MBSR course in addition to ongoing involvement with a MBSR drop-in group. Each subject participated in an audiotaped two-hour semi-structured interview incorporating both data collection and analysis. Central themes evoked by each patient regarding the perceived effect of incorporating meditation into their daily routines were identified in each transcript and then compared with subsequent interviews in an ongoing analysis (Mackenzie et al., 2007). Such an approach emphasizes the phenomenology of subjective experience in the context of lifestyle and disease management; by teasing apart and understanding cognitions conducive to playing an individual along the self-help path, clinicians may augment their clinical understanding of how beneficial lifestyle changes and disease management may be wrought for the sake of bequeathing to patients a greater subjective sense of personal control. Four fundamental themes kept cropping up during the interviews: ‘opening to change’, ‘self-control’, ‘shared experience’, and ‘personal growth’. Collectively these inherent qualities and general outlooks facilitate the advantageous psychological and somatic effects seen in patients and clients after the therapeutic induction of MBSR interventions (Mackenzie et al., 2007). 

        Carmody and Baer (2008) also explored the notion that the practice of MM improves psychological functioning and wellbeing and reduces somatic symptoms using a qualitative research design. They gathered a sample of 206 participants from the MBSR program hosted by the University of Massachusetts Medical School in Worcester, MA, all of whom were suffering from a multifarious continuum of problems including chronic pain, anxiety, illness-related stress, and employment-related stress. The intervention entailed rigorous subjection to seven weeks of an MBSR program that included home mindfulness and meditation practice. Self-report data incorporating total duration of home practice and measures for mindfulness, perceived stress, somatic symptoms, and general state of wellbeing were filed pre- and post-MBSR for each individual day, and each participant was asked to judiciously monitor the trajectory of their progress throughout the intervention period. The 39-item questionnaire called the Five Factor Model Questionnaire (FFMQ) assessed mindfulness; the 53-item Brief Symptom Inventory (BSI) detected the presence of a wide gamut of psychological symptoms; the 115-item Medical Symptom Checklist (MSC) scanned for medical problems; a 10-item scale, the Perceived Stress Scale (PSS) assessed perceived stress; and the compartmentalistic Scales of Psychological Wellbeing (SPW) was used to evaluate subjective feelings about wellbeing (Carmody & Baer, 2008). Results demonstrated significant increases in mindfulness and wellbeing from pre- to post-MBSR, with effect sizes in the moderate to large range. Increases in home mindfulness practice were statistically correlated with positive and constructive changes in the measures quantified (P<.01). In hindsight it appears the latter phenomenon played a fundamental role in mediating the dynamic relationship between meditation practice over intervention duration and the significant reduction in perceived psychological distress and the accompanying somatic symptoms (Carmody & Baer, 2008).

        Several years ago Keng, Smoski, Robins, Ekblad, & Brantley (2012) examined the efficacy of MBSR and self-compassion in alleviating psychological stress and somatic symptoms in a nonclinical sample. The fifty-six individuals selected for the qualitative study were randomly assigned to experimental and waiting-list groups. Pre- and post- assessments for mindfulness, self-compassion, worry, fear, expression and suppression of anger, and difficulty in regulating emotions were completed by all participants. The FFMQ was deployed to measure mindfulness; a 26-item questionnaire named the Self-Compassion Scale was deployed to measure self-compassion; the Affective Control Scale (ACS) quantified fear of emotional disinhibition and losing self-control; a 16-item self-report inventory called the Penn State Worry Questionnaire (PSWQ) assessed generality, excessiveness, and uncontrollability of pathological worry; the Difficulties in Emotional Regulation Scale (DMRS) measured aptitude for emotional regulation; and the Spielberger Anger Expression Scale (SAES) determined the quotient of anger expression to anger suppression (Keng et al., 2012). After the mindfulness treatment, participants demonstrated significantly greater propensities for trait mindfulness, self-compassion and healthy emotional regulation, and significant reductions in the demonstration of unrestrained emotions like rage and excessive worry (Keng et al., 2012).        

        On reflection each experimental design had several methodological limitations that may have confounded the results. Outcomes based on self-selected samples (Speca et al., 2000; Keng et al., 2012), too small a sample size (Reibel et al., 2001), clinical specificity (Mackenzie et al., 2007), and unequal representation across demographics that include age, sex, race, ethnicity, and socioeconomic status (Reibel et al., 2001) are fraught with dangers in that it makes overarching generalizations and extrapolations beyond the existing group of informants impossible. Some experimental designs wherein the absence of a control group (Carmody & Baer, 2008) and the lack of interim assessment points (Keng et al., 2012) are evident would further obfuscate this affair. In many cases valuable information pertaining to prior exposure to MBSR was not made available to the experimenters (Speca et al., 2000; Reibel et al., 2001), increasing prospects of enhanced performance based on prior acquaintance. The vast majority of these studies incorporate self-report and analysis; subjective measures that make pre and post-intervention fluctuations of perceptual phenomena difficult to standardize (Speca et al., 2000; Reibel et al., 2001; Mackenzie et al., 2007; Carmody & Baer, 2008; Keng et al., 2012). What is more the theoretical framework and speculative nature of an assessment method like FFMQ has come under fire with substantial claims that it is not the most effective measure for determining the effects of short-term mindfulness programs (Carmody & Baer, 2008; Keng et al., 2012). Finally, owing to human indiscretion and dishonesty, reported home practice figures (Carmody & Baer, 2008) should always be interpreted with robust caution.

        We know that research into the neurobiological pathways that make it permissible for psychophysiological alterations to occur is still in its infancy, nonetheless a number of fairly recent studies have illuminated how the regulation of emotional experiences wrought by MM in both clinical and nonclinical samples might be accounted for by explanations involving long-term structural and functional changes in the cortical and subcortical networks of the brain. Speaking about negative affect, there is a definite connection between dysphoric symptoms and activation imbalance within the prefrontal cortex whereby the right hemisphere experiences much higher metabolic activity in relation to the left (Baxter, Phelps, Mazziotta, Schwartz, Gerner, & Selin, 1985; Field, Healy, Goldstein, Perry, & Bendall, 1988). Most pivotal for this development was an experimental animal model with rhesus monkeys in the late 90s which revealed an interesting phenomenon: when biased towards the right hemisphere, extreme frontal lobe activation correlated with overly fearful and defensive behaviors as well as abnormally high levels of stress hormones in the blood (Kalin, Larson, Shelton, & Davidson, 1998). In humans these neural phenomena have been causally linked with the symptoms of psychological stress, depression and dysphoric mood (Nikolaenko, Egorov, & Freiman, 1997).

        In light of these neurophysiological studies MM therapies work to somehow rebalance the atypical metabolic activities amongst the abovementioned brain regions. In a recent systematic review Chiesa & Serretti (2010) used neuroimaging techniques and electroencephalography (EEG) studies to identify altered patterns of activation in the prefrontal cortices and anterior cingulate cortices of individuals engaged in MM. There were also significant increases in alpha and delta wave activity during this time, indicating that a cognitive state of deep relaxation had been harnessed. It appears those with dispositional mindfulness engage the integrative capacities of the prefrontal cortex as to inhibit emotional disinhibition and reactivity in the dorsal anterior cingulate cortex and amygdala (Creswell, Way, Eisenberger, & Lieberman, 2007). In recent times a structural Magnetic Resonance Imaging (MRI) study found abundant grey matter in the right anterior insula of experienced MM practitioners (Hölzel, Ott, Gard, Hempel, Weygandt, Morgen, & Vaitl, 2008). The right anterior insula is believed to buttress interoceptive awareness. In another MRI study focusing upon the effects of MBSR on depression (Farb, Segal, Mayberg, Bean, McKeon, Fatima, & Anderson, 2007) it came to light that individuals adhering to the experimental rigor of an 8-week intervention strategy experienced heightened metabolic activity in the dorsolateral and orbitomedial regions of the prefrontal cortex, areas responsible for self-referential mental activity and stimulus-independent thought (Cozolino, 2014). The common denominator here is the propensity of MM to stimulate orbitomedial and dorsolateral prefrontal areas collectively responsible for directing attention, concentration, the inhibitory control of emotional processing, the voluntary suppression of sadness, and the integration of cognition and emotion (Cozolino, 2014)–the same cortical regions and correlated psychological functions believed to be affected by chronic stress, depression, and mood disorders.

        Despite their obvious methodological limitations, the quantitative and qualitative research transcribed in this paper does suggest a plausible correlation between the introduction of an MBST technique, specifically MM, as a lifestyle choice and the amelioration of problematic conditions like psychological stress and mood dysregulation in both clinical and nonclinical samples. Implicit in the empirical discourse are the beneficial effects of MM on psychological and physical health and general wellbeing, as well as the reality that MM can effect top-down causation. If the direction of present neurobiological studies is to be believed then what appears to happen across ontologies is that the purposeful direction of focal attention inhibits negative emotional appraisals which in turn rebalances metabolic dysregulation amongst those brain regions (i.e. the prefrontal cortex, the dorsal anterior cingulate cortex, and the amygdala) adversely impacted by protracted stress, anxiety, and depression.

        Future research should attempt to shed light upon the dose-response relationship and the amount of MM treatment needed to elicit a quantifiable response; the efficacy and proficiency of MM as an independent treatment method to conditions within the scope of traditional psychopathology and medicine; the precise neural pathways and mechanisms involved; the treatment of acute symptomology rather than relapse prevention; and the sustained benefits of MM in differing populations. The incorporation of research with tighter empirical controls and hypotheses into existing treatment models associated with MM would undoubtedly go far in illuminating what prevention strategies might be put in place to minimize the development of psychological stress and increasing feelings of subjective wellbeing in both clinical and nonclinical populations.       

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