The number of studies on emotion regulation has dramatically increased in the past two decades. These studies strengthened our knowledge on how the effectiveness of emotion regulation is crucial for different aspects of healthy affective and social adaptation (Gross, 2001; John and Gross, 2004). Further, dysregulation of emotions typically characterizes mood and anxiety disorders (Gross and Thompson, 2007).

Two major emotion regulation strategies that have been particularly studied are cognitive reappraisal and expressive suppression (Gross and John, 1998). In particular, cognitive reappraisal is defined as the attempt to reinterpret an emotion-eliciting situation in a way that alters its meaning and changes its emotional impact (Lazarus and Alfert, 1964; Gross and John, 2003). Expressive suppression is defined as the attempt to hide, inhibit or reduce ongoing emotion-expressive behavior (Gross and Levenson, 1993; Gross and John, 2003).

Based on an analysis of how emotions unfold over time, it has been argued that cognitive reappraisal and expressive suppression have their primary impact at different points of the emotion-generative process (Figure 1; Gross, 2001; Gross and John, 2003). Specifically, cognitive reappraisal is an antecedent-focused strategy that acts before the complete activation of emotion response tendencies has taken place. It thus might be expected to modify the entire temporal course of the emotional response before emotion responses have been completely generated. Expressive suppression is a response-focused strategy that intervenes once an emotion is already under way and after the behavioral responses have already been fully generated. It thus might be expected to require repeated efforts to manage emotional responses as they continually arise, challenging the individual’s resources.

The usage of cognitive reappraisal allows to implement and produce interpersonal behavior that is appropriately focused on social interaction and is perceived by the others as emotionally engaging and responsive. At odds, expressive suppression comes relatively late in the emotion-generative process and principally modifies the behavioral aspect of the emotional responses, without reducing the subjective and physiological experience of negative emotion, which is not directly targeted by suppression and may thus continue to linger and accumulate unresolved. As expressive suppression comes late in the emotion-generative process, it requires the individual to effortfully manage emotional responses as they constantly occur. These repeated efforts deplete cognitive resources to the detriment of social performances and create a sense of discrepancy between inner experience and outer expression in the individual (Higgins, 1987). The final effect of this sense of inauthenticity can lead to negative feelings about the self, making more difficult the establishment of emotionally close relationships and rather contributing to avoidant, diverted and anxious relational behaviors (Sheldon et al., 1997; John and Gross, 2004).

In the following sections, experimental findings on cognitive reappraisal and expressive suppression will be briefly analyzed. Then, individual-difference findings on the dispositional usage of these two strategies will be taken into account. Finally, brain structural basis and functional activation linked to the habitual usage of cognitive reappraisal and expressive suppression will be discussed in detail.

In experimental studies, participants are exposed to emotion-eliciting situations and randomly assigned to use cognitive reappraisal or expressive suppression strategies or to act naturally (control condition). Experimental studies use powerful research designs: in fact, by manipulating emotion-regulatory processes directly, they can demonstrate the immediate causal effects of particular strategies on dependent variables of interest, such as affective, cognitive and social consequences.

Overall experimental studies have demonstrated that cognitive reappraisal has a positive impact in the affective domain by decreasing negative emotion experience and negative emotion behavioral expression without any increase in physiological activation. At odds, suppression has a negative impact decreasing positive emotion experience and leaving unaltered the subjective negative emotion experience and exacerbating physiological activation (Gross and Levenson, 1993, 1997; Gross, 2002; Mauss et al., 2005; Hayes et al., 2010; Brans et al., 2013).

Cognitively, reappraisal results in unaltered or enhanced behavioral memory performance, while expressive suppression impairs memory performances (Richards and Gross, 1999, 2000; Dillon et al., 2007; Sheppes and Meiran, 2007, 2008; Hayes et al., 2010). Memory advantage for cognitive reappraisal may be subserved by the levels-of-processing effect (Dillon et al., 2007), which is characterized by deeper cognitive analysis of stimuli (Craik and Lockhart, 1972).

In experimental studies on the effects of emotion regulation strategies in social contexts, one member of each dyad is generally asked either to suppress, reappraise or to interact naturally with their conversation partner. When interacting with a person who was using suppression, subjects experienced more stress (i.e., greater increases in blood pressure) than when interacting with a person using reappraisal (Butler et al., 2003; Richards et al., 2003). Thus, while reappraisal has not detrimental effects, the cognitive costs of expressive suppression may concurr to compromise social functioning, as the suppressor fails to take up information needed to respond appropriately to the others and appears not tuned with the flow of the interaction.

Since experimental studies cannot account for the long-term, cumulative consequences of using particular regulatory strategies for the individual’s emotional life, relationships and wellbeing, a complementary, correlational research approach was used. To this aim Gross and John (2003) developed a self-report questionnaire, the Emotion Regulation Questionnaire (ERQ), to assess individual differences in the usage of habitual, dispositional cognitive reappraisal and expressive suppression. Studies using ERQ have shown that the habitual use of these strategies varies systematically between individuals and is stable in time (Gross and John, 2003). Furthermore, cognitive reappraisal and expressive suppression resulted scarcely related to intelligence, social desirability and personality traits, but highly related to the constructs of inauthenticity, coping with stress and mood management (John and Gross, 2004).

Affectively, the use of cognitive reappraisal in everyday life is related to greater experience and expression of positive emotions and lesser experience and expression of negative emotions. By contrast, individuals frequently using expressive suppression experience and express less positive emotions, without differences in the negative ones (Gross and John, 2003; Abler et al., 2010; Larsen et al., 2012). However, expressive suppression may increase negative affect through its strict link with inauthenticity, specifically leading to feel bad about the self and even to depressive symptoms (John and Gross, 2004).

Cognitively, reappraisal has not effects on mnesic performances, while suppression is negatively related to memory, in particular for socially relevant information (Richards and Gross, 2000; Egloff et al., 2006; Hayes et al., 2010; Moore and Zoellner, 2012). In the domains of interpersonal functioning and well-being, cognitive reappraisal was interestingly associated with better psychological health. In fact, individuals who habitually use reappraisal showed lower symptoms of depression, were more satisfied and optimistic, and had higher self-esteem, environmental mastery levels, personal growth, self-acceptance, coping skills, sense of autonomy as well as better interpersonal relationships (Garnefski et al., 2001; John and Gross, 2004). At odds, suppressors feel to have less social support, worse coping abilities, lower life satisfaction, self-esteem, optimistic attitude about the future, higher avoidance and lack of close social relationships and support, all factors increasing the risk for depressive symptoms (Sheldon et al., 1997; John and Gross, 2004). Anyway, interesting recent studies demonstrated that culture has to be a moderator variable of emotion regulation, being the relation between expressive suppression and negative indicators of mental health stronger in the Western culture than in the Eastern one (Soto et al., 2011; Hu et al., 2014).

As the habitual use of emotion regulation strategies shows stable individual differences, it could be possible that these strategies, either as a consequence (i.e., pre-existing individual volume differences lead to differences in emotion regulation) or precondition (i.e., brain region volumes are affected by the usage of emotion regulation strategies) are associated with individual differences in brain volumes and functional activation. Several studies have investigated the underlying neurobiological substrates of cognitive reappraisal and expressive suppression usage.

Following an overview of the studies on brain structural and functional variations associated to the use of cognitive reappraisal and expressive suppression is presented.

Altogether experimental and individual difference studies underpin the crucial role of cognitive reappraisal and expressive suppression in adaptive as well as dysfunctional emotional processing and regulation. Furthermore, brain structural and functional studies depict a resulting brain network constituted by target regions for several emotional regulation processes. Namely, the amygdala has a crucial role in emotion regulation as it processes sensory information from the thalamus and somatosensory cortex and has bidirectional projections with hippocampus (emotional memories) and hypothalamus (physiological activation). The regulation of emotional processes is modulated by an rich net of interconnections among amygdala, insula (enteroception, sense of self) and the cortico-subcortical circuits of the OFC (saliency evaluation of emotional state, selection of adequate behaviors) and ACC (emotional state interpretation, motivated behavior). Also PFC (executive functions, cognitive elaboration) indirectly participates in the emotional regulation through its connections with OFC.

Not by chance association between amygdala gray matter volume and anxiety-related traits/states have been reported in numerous studies in healthy subjects (Barrós-Loscertales et al., 2006; Tottenham et al., 2010; van der Plas et al., 2010; Gerritsen et al., 2012) as well as altered activation and volume in the amygdala are common findings in mood and anxiety disorders (Etkin and Wager, 2007; Drevets et al., 2008; Irle et al., 2010; Atmaca, 2011; Kempton et al., 2011; Sacher et al., 2012). Furthermore, reduced activation of the vmPFC along with amygdala hyperactivation and a dysfunctional recruitment of ACC and dmPFC has been observed in patients with specific phobia and post-traumatic stress disorder (Schienle et al., 2007; Hermann et al., 2009; Milad et al., 2009), most likely indicating reduced cognitive control of emotional reactions. Interestingly, phobic individuals more frequently using cognitive reappraisal have an increased vmPFC activation during extinction learning and recall (Hermann et al., 2013b), probably related to a stronger extinction learning as following a successful CBT (Schienle et al., 2007).

The top-down emotional control network via cognitive reappraisal engages also OFC (Ochsner and Gross, 2005; Hermann et al., 2013b). By contrast, habitual bottom-up use of expressive suppression rely more heavily on the anterior insula (Giuliani et al., 2011a) and dACC/paracingulate cortex and medial PFC volume (Hermann et al., 2013a) as well as on increased insula, PFC and amygdala activation (Ohira et al., 2006; Goldin et al., 2008; Hayes et al., 2010; Vanderhasselt et al., 2013). In this neural correlates pattern the role of the insula emerges, not only in primarily supporting interoception and monitoring emotional awareness and outward emotional expression, but also as a relay point between the bottom-up signals from brain regions involved in emotional responding and inward emotional state, like the amygdala, and bottom-up signals from other regions involved in cognitive regulation and regulation goals, like the PFC (Nunn et al., 2008).

As conclusive considerations, further studies are required to outline more in depth the relations among structural and functional data, trait and state emotion regulation and their interactions. In fact, given the strict relationship between expressive suppression, depression and stress-related symptoms (Moore et al., 2008), the question of whether this strategy is a vulnerability or causal factor remains still open. Otherwise, to evaluate its long term effects on anxiety, depression or other pathologies innovative clinical interventions could be designed training clients to cognitive reappraisal or even positive reappraisal, a recent trying to incorporate meditation mindfulness into cognitive therapy (Garland et al., 2009; Hanley and Garland, 2014).

Finally, another direction for the future studies is to carry out longitudinal researches that, allowing repeated observations of the effects of using particular emotion regulation strategies, would help to understand the causal order of effects of the habitual use of cognitive reappraisal or expressive suppression.

The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.