In a clinical psychology framework, expectations¹ have been defined as future-directed cognitions that focus on the incidence or non-incidence of a specific event or experience (Kube et al., 2016). Based on the Rescorla–Wagner model (Rescorla, 1967), expectations are developed through learning processes (Cleeremans and McClelland, 1991; Colloca and Benedetti, 2009; Colloca and Miller, 2011). Expectations have been identified to contribute substantially to clinical outcome in various medical conditions (Auer et al., 2016; Nestoriuc et al., 2016). Moreover, expectations have been shown to be one of the major components contributing to placebo and nocebo responses in clinical trials (Rief et al., 2008, 2011; Schwarz et al., 2016), and expectations can substantially enhance the effects of drug-specific components (see Kube and Rief, 2016 for a review). With regard to antidepressant clinical trials, large placebo effects have been reported (Kirsch and Sapirstein, 1998; Kirsch et al., 2002, 2008, Rief et al., 2009), and they are assumed to be mainly based on expectation mechanisms (Shedden Mora et al., 2011; Rutherford et al., 2016). Given the great impact of expectancies in clinical research, Rief et al. (2015) have discussed expectancies as core features of mental disorders (Rief et al., 2015). For major depressive disorder (MDD), there is evidence that people suffering from MDD hold situation-specific dysfunctional expectations which may be elicited by depressive core beliefs (Kube et al., 2016). Clinical observations suggest that these expectations are maintained despite experiences that are contrary to patients’ expectations (“expectation violation”) (Rief and Glombiewski, 2016). Surprisingly, this observed persistence of expectations in MDD has not yet been investigated in empirical studies. In this perspective article, we argue that it is worthwhile to investigate the maintenance of expectations in MDD, and we provide a theoretical framework for it with the aim of inspiring empirical research into this neglected phenomenon. This could help to develop psychological interventions aiming at enhancing expectation change and could thus substantially improve current cognitive behavioral treatment (CBT) of MDD.

Exposure therapy for the treatment of anxiety disorders has recently focused on disconfirming disorder-specific expectations by maximizing the discrepancy between patients’ expectations and actual situational outcomes in expectation-violating situations, which is discussed as promising approach to modify patients’ expectations and thereby reduce anxiety symptoms (Craske et al., 2014; Craske, 2015). In MDD, however, disorder-specific expectations are less obvious: people suffering from MDD often report somatic symptoms (such as sleep disturbance, loss of appetite etc.) and negative mood, but may be less aware of cognitions such as expectations (Beck, 2011). Prior research has indicated that (treatment) outcome expectations (Greenberg et al., 2006; Price et al., 2008), self-efficacy expectancies (Ludman et al., 2003; Gopinath et al., 2007; Gordon et al., 2011), and global expectations about future events (Strunk et al., 2006; Vilhauer et al., 2012) predict the course of depressive symptoms. However, situation-specific expectations resulting from depressive core beliefs have received limited attention in psychotherapy research. Similarly, CBT of MDD has primarily focused on present-focused cognitions and automatic thoughts by using cognitive and behavioral interventions (such as cognitive restructuring and behavioral experiments), while rigorously disconfirming future-directed expectations has so far received less attention. A more focused examination of patients’ expectations may be advantageous for optimizing psychological interventions (Rief and Glombiewski, 2016).

This is especially important because MDD has been shown to have a high relapse rate (Judd et al., 1998; Lin et al., 1998; Solomon et al., 2000; Pintor et al., 2003; Eaton et al., 2008; Moffitt et al., 2010). According to Risch et al. (2012), relapse may be due to the reactivation of dysfunctional thoughts when confronted with new stressful events. Moreover, a substantial group of patients does not respond to usual CBT (Hofmann et al., 2012; Button et al., 2015; Beard et al., 2016). We hypothesize that the long-term efficacy of CBT could be increased by more rigorously addressing the mechanisms underlying the persistence of dysfunctional expectations. Before discussing these clinical implications, we first address in more detail the phenomenon of expectation persistence.

Rief et al. (2015) proposed a theoretical model to explain the development and maintenance of expectations. According to this model, expectations are shaped by learning processes, as well as by social influences and individual differences. After being confronted with experiences that are contrary to one’s expectations, expectations can either be changed or maintained (Rief et al., 2015). We suggest that healthy individuals are able to change their expectations after expectation-violating experiences. For instance, though many people may initially expect to fail when attempting a novel difficult task, healthy individuals may modify their expectations about future performance after receiving feedback indicating that they performed well. However, we suggest that among individuals suffering from MDD expectations are often maintained despite experiences that are contrary to their expectations. We argue that this persistence of expectations despite contradictory experiences is a core feature of MDD, and that the maintenance of expectations in MDD is due to maladaptive information processing involving a process called “immunization.”

To empirically examine the hypothesized phenomenon of expectation maintenance in MDD, we propose a stepwise experimental approach (see Table 1). First, researchers should attempt to empirically examine the clinical observation that people suffering from MDD tend to maintain their expectations despite expectation-violating experiences. For this purpose, researchers could focus on explicit expectation regarding personal achievement (e.g., “I will be successful in working on an unknown test”), and they could ask participants to complete an unknown test which is said to be very difficult. Then, participants could be given standardized performance feedback that is surprisingly positive. Thereby, it could be examined whether subjects changed their initial expectations after receiving expectation-violating feedback; that is, the possible change of expectations from pre to post would be the dependent variable. At the same time, the hypothesized immunization process as an underlying mechanism could be examined by exploring the reasons for expectation change vs. expectation maintenance.

After this exploratory approach, it may be useful to experimentally manipulate the appraisal of the expectation-violating situation to impede or enhance immunization. For this purpose, experimenters could vary whether or not participants are guided to consider the expectation-violating experience as exceptional. For instance, one could provide standardized information to participants suggesting that the test completed either is or is not useful for predicting achievement in other situations. Thus, it can be examined to what degree the manipulation of the perceived relevance of the expectation-violating experience influences expectation change. Another approach for experimentally manipulating immunization could be the induction of self-focused rumination vs. distraction after an expectation-violating situation. Based on Lyubomirsky et al.’s (2003) paradigm, it is hypothesized that self-focused rumination in individuals with MDD triggers negative thoughts about perceived past failures, which may facilitate immunization and may therefore additionally contribute to expectation maintenance. To investigate self-concept relevance as a possible moderating variable, correlational analyses could examine whether expectation maintenance is more likely if the expectations are closely related to the individual’s self-concept. If correlational analyses yield promising results, researchers could experimentally vary whether or not the expectations examined in the study are associated with self-concept. Finally, clinical studies might examine whether enhancing CBT with expectation focused interventions (see also Rief and Glombiewski, 2016) increases therapy success relative to treatment as usual.

A better understanding of the persistence of expectations in MDD would have several implications for CBT for MDD. Within CBT for MDD, behavioral experiments are an effective method of testing automatic thoughts in order to facilitate cognitive restructuring (Dobson and Hamilton, 2003; Beck, 2011; Dobson, 2016). Given the relevance of disorder-specific expectations in MDD, we encourage therapists to more specifically focus on patients’ expectations when designing behavioral experiments, as the “if-then” structure of expectations (as opposed to other automatic thoughts) makes them susceptible to falsification (Kube et al., 2016). That is, behavioral experiments can serve as expectation-violating situations insofar as patients can gain experiences that are contrary to their expectations (Craske et al., 2014). However, clinical experiences suggest that experiences contrary to patients’ expectations do not always result in successful change of expectations (Rief and Glombiewski, 2016). In such cases, it may be worthwhile to actively explore the reasons for the maintenance of expectations in order to impede immunization processes, which could improve therapy success in multiple ways.

First, if a patient considers the experience in a behavioral experiment to be an exception, the therapist should discuss whether this appraisal is accurate or useful. If necessary, behavioral experiments may subsequently be repeated under different circumstances to call the patient’s appraisal into question. Thus, the generalizability of the experience gained in a behavioral experiment should be emphasized to prevent immunization processes. Second, if a patient fundamentally questions the credibility of the experience, the therapist might help the patient to re-examine the validity of the experience. Third, therapists should carefully consider whether the expectations tested in a behavioral experiment are closely related to the patient’s self-concept, and should be aware that if so, change in expectations may be less likely. Such awareness may prevent disappointment for both patient and therapist, and the therapist can motivate the patient to change his or her behavior, e.g., by discussing the consequences of the behavior. Fourth, in addition to exploring the reasons for maintenance of expectations after a behavioral experiment, it may be useful to discuss with the patient the conditions under which he/she would change his/her expectations before engaging in the behavioral experiment. This would allow the therapist and patient to agree on the conditions for the behavioral experiment such that the patient would consider a violation of his/her expectations to be a valid experience. This procedure might help to prevent post hoc confirmation of expectations via immunization.

Given the high relapse rates in MDD (Judd et al., 1998; Lin et al., 1998; Solomon et al., 2000; Pintor et al., 2003; Eaton et al., 2008; Moffitt et al., 2010), rigorously addressing patients’ expectations may be helpful with respect to long-term benefit from therapy, as patients can be encouraged to test future dysfunctional expectations independently after therapy completion. If CBT were to enable patients to prevent dysfunctional immunization processes, this could result in additional positive experiences which in turn could impede the reactivation of dysfunctional thoughts (Risch et al., 2012).

Considering the maintenance of expectations may also be useful for the treatment of other mental disorders. Modifying patients’ expectations through exposure to expectation-violating situations has been discussed as a promising approach in the treatment of anxiety disorders (Craske et al., 2014; Craske, 2015), obsessive compulsive disorders (Craske et al., 2014), and chronic pain (Riecke et al., 2013). We believe that impeding immunization processes (as discussed for MDD in this article) might also be an important mechanism of change in these disorders. Thus, we hope that the proposed theoretical model for the persistence of expectations will inspire future research with the aim of optimizing cognitive-behavioral therapy by preventing immunization processes not only in MDD, but also in other mental disorders involving dysfunctional expectations.

The maintenance of expectations despite experiences that are contrary to expectations is believed to be a core feature of MDD. We suggest that this persistence of expectations is due to maladaptive information processing in MDD, in particular, immunization processes. Immunization is hypothesized to be especially pronounced if an individual’s expectations are closely associated with his or her self-concept. This should be examined in a series of experimental studies and could provide useful information for the treatment of depression. Carefully addressing the reasons for expectation persistence may be useful for optimizing psychological interventions, hence increasing the long-term efficacy of CBT.

TK: Did the major part of the work with regard to conception and design; mainly contributed to the development of the manuscript; approves the manuscript to be published; agrees on being accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. WR: Substantially contributed to the conception of the work; revised the manuscript critically for important intellectual content; approves the manuscript to be published; agrees on being accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. JG: Substantially contributed to the conception of the work; revised the manuscript critically for important intellectual content; approves the manuscript to be published; agrees on being accountable for all aspects of the work in ensuring that.

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