Meditation-based interventions reduce the relapse risk in recurrently depressed patients. Randomized trials utilizing neurophysiologic outcome measures, however, have yielded inconsistent results with regard to a prophylactic effect. Although frontal brain asymmetry, assessed through electroencephalographic (EEG) alpha activity (8–13 Hz), is indicative of approach vs. withdrawal-related response dispositions and represents a vulnerability marker of depression, clinical trials have provided mixed results as to whether meditation has beneficial effects on alpha asymmetry. Inconsistencies might have arisen since such trials relied on resting-state recordings, instead of active paradigms under challenge, as suggested by contemporary notions of alpha asymmetry.
Due to the high prevalence of depression and the fact that it is frequently recurrent, tremendous effort has been made to develop and evaluate forms of medical and psychotherapeutic maintenance therapy (Dobson et al., 2008 and Teasdale et al., 2000). With regards to psychotherapy, a particularly effective approach is to be seen in mindfulness-based interventions, i.e. interventions involving exercises of mindfulness meditation (Segal et al., 2002). The term mindfulness represents a quality of consciousness which is characterized by an open, non-judgmental attitude toward anything arising within the field of awareness, combined with refined, purposeful attention (Hanh, 1996). Mindfulness is traditionally fostered through meditation exercises in which individuals acquire the skill to redirect their attention toward physical sensations of their breath, as distracting cognitions and emotions arise (Kabat-Zinn, 1990 and Keune and Perczel-Forintos, 2010). As a consequence, patients at risk for depression may reframe phenomena which may endanger their remitted state, such as dysfunctional attitudes and sad mood, in a meta-cognitive perspective, and experience them as impermanent events, rather than facts (Teasdale et al., 2002). It has further been suggested that the non-judgmental attitude which characterizes mindfulness, is associated with a reduction in avoidant behavior and increased affect tolerance (Bishop et al., 2004). In line with these notions, structured interventions like mindfulness-based cognitive therapy (MBCT; Segal et al., 2002) and mindfulness-based stress-reduction (MBSR; Kabat-Zinn, 1990) have been shown to reduce residual depressive symptoms, trait rumination and cognitive reactivity to sad mood (Keune et al., 2011a, Kingston et al., 2007, Raes et al., 2009 and Ramel et al., 2004).
The current study provides original information on the potential neural working mechanisms underlying mindfulness practice in female patients suffering from major depression. We suggest that further studies on this topic are warranted, which verify the current results by means of a randomized design, an optimized control condition and by including male participants.
Results of the current study are also of relevance for the ongoing discourse on the role of alpha asymmetry as an indicator of the capability to regulate emotions during challenging circumstances (Coan et al., 2006). Regarding intervention studies utilizing alpha asymmetry as an outcome measure, they suggest that putative effects need to be considered in a corresponding dynamic framework. Consideration of this issue is particularly important for future studies, as active conditions appear to be required to pick up transient alterations related to meditation practice.
