From the perspective of cognitive behavioral theory, CG arises from an individual’s inability to accept the loss of the loved one, in tandem with maladaptive grief- and death-related interpretations and avoidant coping strategies [5]. Central to a cognitive behavioral framework is that psychopathology persists because of distorted, maladaptive interpretations of ambiguous or personally meaningful information and problematic behavior stemming from these biased appraisals, which are mutually reinforcing. In the case of CG, bereaved individuals make biased grief-related appraisals about themselves, the future, and their own reaction to the loss; and engage in avoidance behavior that impedes healthy coping with the loss. For example, individuals may feel they are to blame for the loss (e.g., I could have stopped it if I had been there), they have no purpose or sense of meaning without that person, or that they are not reacting normally to the loss (e.g., If my grief diminishes that means I don’t care about the person). The loss of a loved one can also violate previously held beliefs about an individual’s sense of self, their purpose, and their future [5, 6]. Consequently, loss may make the bereaved feel that their lives are meaningless without their loved one. They may also believe that experiencing any positive emotionality after the death is disrespectful to the memory of the deceased or renders the loss less significant. Thus, faulty global, negative, and internal cognitions about the self and their situation prevent those with CG from seeking out support or engaging in previously meaningful and often pleasurable behaviors (e.g., social activities, places, or hobbies associated with the deceased) that foster adjustment to the loss.

One specific model, Boelen’s cognitive behavioral model of CG , further posits that bereaved individuals fail to adequately integrate information about the loss with existing, prior knowledge. A bereaved individual’s initial schema of the deceased is that of a living individual characterized by elements of both a unique and shared past, and of possibilities of future interaction. While this schema is updated after the loss in most bereaved individuals, Boelen hypothesized that for those with CG information about the permanence of separation is not sufficiently integrated with older information about the relationship with the deceased [5, 6]. Essentially, for the individual with CG, factual knowledge that separation is permanent does not get linked with information about the relationship with the deceased. Consequently, bereaved individuals with CG continue to experience grief as distinct (i.e., not integrated with other memories) and emotionally painful [5, 6]. From this cognitive behavioral perspective, this explains why bereaved individuals have difficulty accepting the loss as final, experience “unrealness” about the death, and continue to feel shock when they are reminded of the loss [5, 6]. Each reminder of the finality of the situation (e.g., that their loved one is permanently gone) is thus at odds with the cognitive framework of individuals with CG and consequently induces distress.

Accordingly, cognitive behavioral theories explain why individuals with CG engage in cognitive and behavioral avoidance of loss reminders that provoke this affective distress. Individuals with CG may avoid any objects, situations, or thoughts that may cause them to experience distress or confront the finality of the loss [5, 6]. In the context of grief, this behavioral avoidance includes avoiding people, places, situations, or things that are associated with the deceased. Additionally, individuals may also engage in cognitive avoidance, attempting not to think about the events surrounding the loss, which is negatively reinforcing and perpetuates the cycle of nonacceptance. Thus, cognitive behavioral theory-informed interventions may address an individual’s reluctance to accept the loss, the faulty cognitions, and avoidance behaviors that prolong grief symptoms and perpetuate the syndrome.

The dual-processing model of adaptive coping also emerged as a theory to understand the maladaptive patterns of prolonged grief that arise after the loss of a loved one [7]. Similar to the cognitive behavioral framework, the dual-processing model of adaptive coping acknowledges that persistent grief arises when bereaved individuals have difficulty accepting the loss of their loved ones, and develop maladaptive cognitive and behavioral coping patterns. As with cognitive behavioral theory, avoidance of loss-related stressors is central to the dual-processing model of adaptive coping. Additionally, bereaved individuals are prone to avoid engaging in positive behaviors so that they may remain connected to the deceased [7, 8]. However, the theories diverge somewhat to the extent that the dual-processing model emphasizes the failure of coping mechanisms. The theory posits that typically, bereaved individuals experience an oscillation between two orientations: loss-orientation and restoration-orientation [7]. Most bereaved individuals spend time acknowledging the loss (e.g., attending a funeral, talking about the deceased with others, mourning the loss while looking at photos) and re-engaging in life without the deceased (e.g., attending a social gathering without the deceased, going to a restaurant that used to be enjoyed together, discarding items that belonged to the deceased). According to dual-processing model, CG develops due to a failure to alternate and find balance between these two orientations, such that bereaved individuals with CG spend their time focusing solely on the loss and fail to re-engage in positive life activities, which is thought to be motivated by a desire to remain connected to their lost loved one [7].

The attachment theory of CG emphasizes the attachment quality and style of the relationship between the bereaved and the deceased. Attachment theory developed from research on infant–mother attachment styles that were broadly characterized as either secure or insecure, depending on the infant’s response to the caregiver’s absence and subsequent ability of the caregiver to soothe the infant following a period of absence [9–11]. Adults, not just infants, are motivated to attach and adult attachments are also characterized by sexuality and caregiving systems, or the need to both care for others and be cared for [12]. Attachment is considered an intrinsic biological motivation that when disrupted, either through separation or death of a loved one, leads to significant distress [10–12]. Hofer [13] theorized that loss of an attachment figure leads to a dysregulation of an individual’s biological regulatory system, since that attachment figure plays a central role in their affective, attentional, and motivational processes [12]. Stated another way, when separation occurs (e.g., a mother temporarily leaves a toddler alone, or individual loses his/her spouse), the regulatory system becomes disrupted and is associated with emotional distress such as crying (affective process), difficulty attending to or concentrating on other stimuli (attentional process), and decreased or aimless involvement in other activity (motivational process). A basic premise of the theory is that loved ones (initially caregivers, but later intimate partners and even children) are viewed as “safe havens” or secure bases from which an individual explores and interacts with the world. That is to say, individuals with secure attachments function in the world autonomously, but return to the attachment figure as a source of support and comfort. As children age (and become capable of symbolic, cognitive processing), they develop mental representations of the attachment figure that can be a source of comfort even when physically separated.

Thus, whereas infant relationships require close physical proximity between mother and child, adult relationships rely more heavily on internalized representations (i.e., cognitive symbols, ideas, or images) of the attachment figure (e.g., parent, spouse, child) informed by the quality and functioning of the relationship [12, 13]. According to attachment theory of grief, the loss of an important attachment figure consequently changes an individual’s sense of a security in the world and impacts interpersonal functioning [12]. From this perspective, the loss creates a mismatch between mental representations of the loved one and the sudden change in the bereaved person’s relationship with the deceased, leaving the bereaved with a strong sense of yearning for the loved one and sense of disbelief over the loss [14]. Importantly, the loss of a close relationship impedes one’s ability to construct a meaningful sense of self without that person [8]. Thus, according to the attachment theory, the death of a loved one usually produces a state of traumatic loss and symptoms of acute grief that will evolve into a state of CG if an individual is unable to accept the reality of the death or reestablish their identity without that person [12].

In summary, three psychological theories of CG, cognitive behavioral theory, the dual-processing model of adaptive coping, and attachment theory, have emerged to describe the underpinnings and phenomenology of CG. Central to all three theories is the inability to accept the reality of the death, which consequently disrupts bereaved individuals with CG from maintaining a meaningful sense of self and purpose. Additionally, across all three theories, bereaved individuals with CG develop maladaptive coping strategies as a result of the loss, which has led researchers to develop evidence-based cognitive behavioral therapeutic interventions that directly target grief-related behavioral and cognitive avoidance and help individuals to re-engage in their life in meaningful ways. In the following section, we will review the principles and empirical evidence for two specific approaches based on these theories: cognitive behavioral therapy (CBT) and complicated grief treatment (CGT). Other therapeutic approaches, such as narrative therapy, similarly based on dual processing theory, is described in a separate chapter (Chap. 8).

Guided by theory, cognitive behavioral therapy (CBT) for grief incorporates specific techniques to encourage acceptance of loss, modify maladaptive grief-related appraisals, and reduce avoidance. CBT has been delivered in group and individual settings and typically consists of 12 sessions. CBT consists of four core treatment interventions including psychoeducation, cognitive restructuring, exposure, and behavioral activation.