Treatment component studies: Are treatment mechanisms specific to MMBI?

As the foregoing review indicates, there is accumulating evidence that MMBI may affect therapeutic change through attention regulation, enhanced body awareness and emotion regulation, and changes in the sense of self. Because MMBIs are group-based multi-component interventions, dismantling studies are needed to isolate the treatment components and differentiate them from non-specific effects of treatment, such as therapist effects or the benefits of group support, and from other active treatment components, such as breath- focused awareness practiced outside of mindfulness meditation, exercise, and cognitive therapy. Dismantling and other treatment component studies could also address questions about whether mindfulness as a form of attending to the present is specific to Buddhist-based mindfulness interventions or is a more broadly evoked capacity.

Some studies of MMBI components suggest that mindfulness may be the product of both attention and breath regulation that is not specific to mindfulness meditation. A single-session mindfulness versus sham meditation study of college students found that both were associated with increased states of mindfulness and improved mood and distress relative to a book-reading control group. A convincing sham condition would control for the demand characteristics and expectancy effects associated with mindfulness practice; in this study the sham and mindfulness groups did not differ in the extent to which they felt they were meditating during the exercises (Johnson et al. 2013). The sham directions to sit quietly and breathe deeply suggest that attention to breath regulation may be associated with increased mindfulness and other outcomes, a possibility explored by studies of the effects of breathing exercises. A study of inhalation/exhalation (i/e) ratio found that lower ratio breathing was associated with greater mindfulness than the high ratio condition (Van Diest et al. 2014). Although mindfulness instruction typically doesn’t suggest modifications to respiratory rate, mindful awareness of breathing often results in spontaneous breath slowing (Kristeller and Rikhye 2008), which is in turn related to a shift toward lower i/e ratio (Van Diest et al. 2014). Even a brief, 15-minute period of breath-focused attention was associated with better mood and emotion regulation among college students relative to unfocused attention and worrying (Arch and Craske 2006), suggesting that breath-focused attention, rather than extensive training in OM mindfulness, was associated with better outcomes.

The effects of MMBI components on psychological well-being have been tested in sham-controlled designs. For example, a three-session mindfulness intervention with college students significantly reduced overall negative mood and heart rate relative to sham meditation and a control, though the sham meditation also produced pre/post reductions in state anxiety and tension (Zei- dan et al. 2010), suggesting there was a common factor to both conditions.

Physical exercise is a component of MBSR and related MMBI in the form of hatha yoga. Exercise is well known to produce substantial treatment effects on depression (Josefsson et al. 2014), which raises the question of the relative contributions of MMBI treatment components to mood and well-being outcomes. Pre/post comparisons of participants in MBSR classes revealed that practice time for mindful yoga was associated with more improvements in outcome variables than body scan, sitting meditation, or practice in daily life; notably, amount of practice in daily life was unassociated with pre/post improvements (Carmody and Baer 2008). Similar findings of the differential effectiveness of hatha yoga come from a randomized study of the three primary components of MBSR-related MMBI, namely sitting mindfulness meditation, mindful yoga, and body scan, which found that yoga was associated with greater improvements in psychological well-being than the other two components, and that both sitting meditation and hatha yoga were associated with greater pre/post improvements in emotion regulation than body scan. Participants in the sitting meditation condition had greater improvements in non-evaluative attention than the body scan participants, as might be expected given the repeated and explicit instructions against judging experience in mindfulness meditation (Sauer-Zavala et al. 2012). Intriguingly, an RCT of MBSR versus aerobics for social anxiety disorder found that MBSR and aerobics had equal therapeutic outcomes (Jazaieri et al. 2012). Similarly, a comparison of MBSR and Argentine tango for major depression reported nearly identical effect sizes for MBSR and tango in terms of depression but found that only tango reduced stress levels (Pinniger et al. 2012). In addition, pre/post increases in mindfulness were associated with being in the tango, but not the mindfulness, class. These two studies in which outcomes of physical activities matched those of the mindfulness conditions suggest the possibility that the physical exercise component of MMBI contributes much to the observed treatment effects.

Likewise, CBT is known to have potent treatment effects and is a component of MMBIs such as MBCT and MBRP. A randomized dismantling trial of MBCT for depressive remission found that relapse rates were equivalent across the three treatment arms of MBCT (46%), an active cognitive treatment (50%), and treatment-as-usual (53%), though when considering those with a history of severe childhood trauma, MBCT was associated with lower relapse rates (41%) than treatment-as-usual (65%) and cognitive treatment (54%) (Williams et al. 2014).

Taken together, studies indicate that components of MMBI that promote capacities such as attention and emotion regulation are effectively taught in MMBI, though these capacities can be evoked through other means, such as practice of breath-focused attention in non-meditation contexts, hatha yoga and other types of exercise, and CBT. Much of the work in isolating treatment components has used college students as participants, so implications for work with persons with symptoms of clinical severity are unclear.

 
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