PGD is intended to describe severe and disabling grief reactions that do not remit in the 12 months after the death of a significant other. The core of the diagnosis includes persistent yearning or missing the deceased, and preoccupation with the circumstance of the death. In addition to this central element, there are additional symptoms that could be present such as difficulty accepting the death, feelings of loss of a part of oneself, anger about the loss, guilt or blame regarding the death, or difficulty in engaging with new social or other activities due to the loss. Importantly, these persistent reactions need to be outside one’s cultural norm, recognizing the variability in societal frameworks of mourning and grief. Proponents of PGD support the difference of symptoms of persistent grief from those observed in the normative reactions to bereavement in the acute phase, they believe not all grief is normal, in particular, prolonged, unresolved, intense grief is not normal. From the PGD perspective, grief symptoms themselves are neither atypical nor pathological and PGD is characterized by normal symptoms of grief that remain too intense for too long. That is, all symptoms of grief are normal, but some combination of their severity and their duration is not. For PGD, the pathology is in the time course of the symptoms, not in the symptoms per se [25].

PGD has been proposed as a new diagnosis for the International Classification of Diseases-11 (ICD-11) new group “Disorders specifically associated with stress”, describing abnormally persistent and disabling responses to bereavement. This new ICD-11 section includes adjustment disorder, PTSD, and complex PTSD, identifying a proposed group of disorders specifically related to stress. Specifically, this set of conditions have distinct psychopathology and require prior exposure to an external stressful event, or adverse experiences of exceptional character or degree; events may range from less severe psychosocial stress (life events) to the loss of a close other, single traumatic events, and repeated or prolonged traumatic stress of exceptional severity. The introduction of PGD is a response to the increasing evidence of a distinct and debilitating condition that is not adequately described by current ICD diagnoses. It is defined as a severe and enduring symptom pattern of yearning or longing for the deceased or a persistent preoccupation with the deceased. This reaction may be associated with difficulties accepting the death, feelings of loss of a part of oneself, anger about the loss, guilt or blame regarding the death, or difficulties in engaging with new social or other activities due to the loss. Importantly, prolonged grief disorder can only be diagnosed if symptoms are still apparent after a period of grieving that is normative within the cultural context (e.g. 6 months or more after the death), the persistent grief response goes far beyond expected social or cultural norms, and the symptoms markedly interfere with one’s capacity to function. If normative grieving in the individual’s culture goes beyond 6 months, the duration requirement should be extended accordingly. Although most individuals report at least partial relief from the acute pain of grief by around 6 months following bereavement, those who continue experiencing severe grief reactions beyond this time frame are likely to have a significant impairment in their general functioning [21]. Many studies from around the world, including both Western and Eastern cultures, have identified a small but significant portion of bereaved people who meet this definition.

It is important to note that diagnostic criteria have evolved over time, such that some studies might be referring to PGD using CG criteria and vice versa, adding to some confusion in the field. Factor analyses repeatedly demonstrated that the central component of PGD (yearning for the deceased) is distinct from nonspecific symptoms of anxiety and depression. Distinctive neural dysfunctions and cognitive patterns associated with PGD have been described [23, 43] and patients can experience serious psychosocial and health problems, including other mental health difficulties such as suicidality and substance abuse, harmful health behaviours, or physical disorders such as high blood pressure and elevated rates of cardiovascular disorder [44].

Regarding pharmacological treatment, PGD does not respond to antidepressant medication though bereavement-related depressive syndromes do [45]. Psychotherapy approaches that strategically targets the symptoms of PGD has been shown to alleviate their occurrence more effectively than treatments that target depression [18]. The introduction of PGD as a diagnosis has caused debate because of concerns that it could pathologize normal grief responses [46]. The Working Group considered this issue thoroughly and emphasized several points: the diagnostic requirements being carefully drawn to respect the variation of “normal” processes and to pay attention to cultural and contextual factors; the diagnosis only applying to that minority (<10%) of bereaved people who experience persistent impairment; the recognition of marked cultural variations in grief manifestations to be taken into account for diagnostic decisions; the consideration that many people will experience fluctuating distressing grief responses beyond 6 months from the death of close persons not being necessarily candidates for a PGD diagnosis due to a lack of persistence and debilitation.

Epidemiological findings have corroborated PGD as a public health issue and that accurate identification of people with the disorder could reduce the likelihood of inappropriate treatment. Proposed diagnostic criteria for PGD are reported in Table 14.2.

The latest edition of the Diagnostic and Statistical Manual (DSM-5, [24]) introduced for the first time extremely important changes for what concern pathological grief reactions, not only suggesting diagnostic criteria for a possible disorder related to a pathological grief reaction, but also better delineating the boundaries with other mental disorders potentially related to loss.

Grief has been addressed in different chapters of the DSM-5. First a new pathological entity named PCBD was introduced in the section III chapter Conditions for Further Study. Important changes were also addressed to diagnostic criteria for Major Depressive Disorder (MDD) when related to a loss, with the elimination of the so-called bereavement exclusion . Finally, within the chapter of “Trauma and Stressor related disorder” are included disorders also potentially related to significant losses, such as PTSD, Acute Stress Disorder (ASD) , and Adjustment Disorder (AD) .

With the inclusion of PCBD, the DSM-5 recognizes the possible development of persistent and debilitating symptoms of grief in a minority of subjects facing the loss of a significant other. The construct of PCBD originates from the strong evidence that there is a set of grief symptoms that forms a unitary dimension, distinct from symptoms of depression, PTSD, and other anxiety disorders, that is associated with severe distress and disability, even when controlling for co-occurring symptoms of depressive and anxiety disorders [21, 23, 44]. Although empirically based criteria sets for both PGD and CG had already been proposed, the DSM-5 Workgroup chose a new name, PCBD, and set of diagnostic criteria by reviewing the literature and obtaining expert consultation and consensus discussions that incorporated aspects of both PGD and CG.

PCBD is diagnosed only if at least 12 months (6 months in children) have elapsed since the death of someone with whom the bereaved had a close relationship (Criterion A). This time frame discriminates normal grief from persistent grief. The condition typically involves a persistent yearning/longing for the deceased (Criterion B1), which may be associated with intense sorrow and frequent crying (Criterion B2) or preoccupation with the deceased (Criterion B3). The individual may also be preoccupied with the manner in which the person died (Criterion B4). Six additional symptoms are required, including marked difficulty accepting that the individual has died (Criterion C1) (e.g. preparing meals for them), disbelief that the individual is dead (Criterion C2), distressing memories of the deceased (Criterion C3), anger over the loss (Criterion C4), maladaptive appraisals about oneself in relation to the deceased or the death (Criterion C5), and excessive avoidance of reminders of the loss (Criterion C6). Individuals may also report a desire to die because they wish to be with the deceased (Criterion C7); be distrustful of others (Criterion C8); feel isolated (Criterion C9); believe that life has no meaning or purpose without the deceased (Criterion C10); experience a diminished sense of identity in which they feel a part of themselves has died or been lost (Criterion C11); or have difficulty engaging in activities, pursuing relationships, or planning for the future (Criterion C12). PCBD requires clinically significant distress or impairment in psychosocial functioning (Criterion D). The nature and severity of grief must be beyond expected norms for the relevant cultural setting, religious group, or developmental stage (Criterion E). Although there are variations in how grief can manifest, the symptoms of PCBD occur in both genders and in diverse social and cultural groups. Some individuals may also experience hallucinations of the deceased (auditory or visual) in which they temporarily perceive the deceased’s presence (e.g. seeing the deceased sitting in his or her favorite chair). They may also experience somatic complaints (e.g. digestive complaints, pain, fatigue), including symptoms that had been experienced by the deceased. PCBD can occur at any age, beginning after the age of 1 year. Symptoms usually begin within the initial months after the death, although there may be a delay of months, or even years, before the full syndrome appears.

In recognition of their lack of validation, PCBD criteria were included in section 3 of DSM-5 “Conditions for Further Study”. As PCBD is only found in this appendix, and not considered a “real” diagnosis, sufferers may not be recognized at all or only treated for depression without receiving a grief-specific psychotherapy. However, in the DSM-5, interestingly, PCBD was listed as an example of the “Other Specified Trauma- and Stressor-Related Disorders” diagnostic category. The alternative “usable” diagnosis, adjustment disorder, which would fit the description of some of patients with prolonged grief, is defined by a duration of not more than 6 months “once the stressor or its consequences have terminated” [24]. Treatment studies reveal that time between the actual loss and start of treatment is several years on average [47, 48], suggesting that adjustment disorder the best fitting diagnosis either. Currently, there is considerable interest in assessing the ability of PCBD criteria to accurately identify bereaved individuals in need of clinical intervention (e.g. [49, 50]).

Prior to the 1980 publication of the Diagnostic and Statistical Manual-Third Edition (DSM-III), bereavement was not part of psychiatry’s official nomenclature. The bereavement exception only became an issue with the publication of the DSM-III. In this latter in fact, bereavement was a V code for a “Supplementary Classification of Factors Influencing Health Status and Contact with Health Services” [51]. The DSM-III distinguished between uncomplicated, or a normal reaction to loss, and complicated grief: “A full depressive syndrome frequently is a normal reaction to such a loss, with feelings of depression and such associated symptoms as poor appetite, weight loss, and insomnia [uncomplicated grief]”. However, morbid preoccupation with worthlessness, prolonged and marked functional impairment, and marked psychomotor retardation are uncommon and suggest that the bereavement is complicated by the development of Major Depressive Disorder (MDD). Unless an individual experienced severe expressions of grief, he or she was considered to exhibit normal grief. The incentive to include bereavement in the DSM-III came from the need to contextualize bereavement in relation to depressive symptoms. The DSM-III committee noted that depressive symptoms, within the context of bereavement, were a normal reaction to the death of a loved one, whereas if these symptoms occurred outside bereavement, they would be abnormal [52]. Another reason for the reluctance to clinically disentangle grief from MDD is that the symptoms of bereavement and MDD overlap considerably. Sleep disturbance, anhedonia, sad mood, guilt and occasionally suicidal ideation may be present in both conditions [3, 53, 54]. The overall theme that helps one distinguish symptoms of grief from symptoms of MDD is that symptoms of grief are loss centered whereas symptoms of MDD typically are both centered on the self and pervasive.

The addition of the bereavement exclusion to the DSM-III was based on the pioneering series of studies initiated by Paula Clayton and colleagues at the University of Washington in the 1960s and early 1970s [55–59]. These studies were based mainly on bereaved widows and widowers and demonstrated that symptoms of depression are exceedingly common in individuals experiencing normal grief for the loss of a loved one [60]. In the first month of bereavement, study participants often experienced symptoms of MDD, including depressed mood, crying, anorexia and/or weight loss, difficulty concentrating and/or poor memory, and sleep disturbance. Most somatic symptoms dramatically improved by the end of the first year. However, insomnia (48%), restlessness (45%), periodic low mood (42%), and crying (33%) persisted in over one-third of participants [55]. The 1-year incidence of a full MDD was high (47% in the bereaved versus 8% in the non-bereaved controls), but rates appreciably declined over the first year (35–42% of the bereaved at 1 month versus 16% at 1 year) [15]. This work laid the foundation for the bereavement exclusion, as it highlighted the importance of not confusing MDD with a normal phenomenon, grief.

A number of studies on widows and widowers revealing an improvement in their symptoms of depression over time [56]served as the impetus for the guidelines in the fourth edition of the DSM (DSM-IV; [61]). The DSM-IV operationalized the duration of these symptoms as persisting for longer than 2 months after the loss, stating: “The diagnosis of MDD is generally not given unless the symptoms are present 2 months after the loss. However, the presence of certain symptoms that are not characteristic of a “normal” grief reaction may be helpful in differentiating bereavement from a major depressive episode. These include: (1) guilt about things other than actions taken or not taken by the survivor at the time of the death; (2) thoughts of death other than the survivor feeling that he or she would be better off dead or should have died with the deceased person; (3) morbid preoccupation with worthlessness; (4) marked psychomotor retardation; (5) prolonged and marked functional impairment; and (6) hallucinatory experiences other than thinking that he or she hears the voices of, or transiently sees the image of, the deceased person.” These symptoms had to exist for at least 2 weeks, although the diagnosis could not be given until at least 2 months following the death of a loved one. Thus, according to the DSM-IV-TR, an individual who meets all symptomatic, duration and impairment criteria for MDD but is recently bereaved may not have MDD; in contrast, a non-bereaved individual with the same clinical constellation of symptoms, who is recently divorced, impoverished, or disabled, or who cannot identify any recent adversity, does have MDD.

The DSM-5 changed the bereavement exclusion, removing the 2-month waiting period [62]. The new criteria allow a bereaved individual to be diagnosed with major depression after 2 weeks of experiencing symptoms, one of the most contentious changes in the DSM-5. For many, removing the bereavement exclusion became symbolic of the predominant concerns regarding financial incentives and the respective medicalization of “normal” conditions by DSM-5. Part of the outcry against this decision is the worry that clinicians will now overdiagnose MDD, especially in individuals who are “just” grieving [63].

On one hand, there are four major arguments that prompted the removal of the bereavement exclusion in the DSM-5. First, the changes were based on data from two reviews [64, 65] and recent studies finding no major difference between bereavement-related depression and depression caused from other life stressors in terms of risk factors, intensity, characteristics, biology, symptoms, and response to treatment [53, 62, 64, 66, 67]. The second major argument came from three international studies from Lebanon, Denmark, and France [68–70] revealing that individuals who were excluded from the diagnosis of depression due to bereavement actually had more severe symptoms than those with non-bereavement-related depression [53]. Karam et al. [69] reported that the global symptom profile of depressed individuals and their risk for depressive recurrence was similar in bereaved and non-bereaved subjects, and that the duration of illness was actually longer in the bereaved group. Corruble et al. [68] found that subjects who were excluded from the diagnosis of MDD because of current DSM-IV-TR conventions are, if anything, even more severely depressed than MDD controls without bereavement. Results from these studies suggest that bereaved individuals who are excluded from receiving the diagnosis of major depression might develop more severe and/or persisting depression because they are unable to access different treatments for their depression. A third argument for removing the bereavement exclusion in the DSM-5 was that this change would be parallel to existing international criteria in the International Classification of Disease (ICD-10). The unification of the criteria for depression related to bereavement in the DSM and the ICD would make the diagnosis more consistent. Finally, the last rationale for removing the bereavement exclusion in the DSM-5 was that clinicians should be able to properly distinguish “adaptive” grief from more serious reactions of grief including feelings of isolation and the inability to be consoled. Moreover, clinicians should evaluate patients’ experiences and examine phenomenological differences rather than solely using diagnostic checklists [71]. This idea of the phenomenology of grief comes from the notion that there is a distinction between normal sorrow and severe depression that clinicians are best able to evaluate. This idea is that sorrow, bereavement, severe grief, and depression have biological differences and that there is a range of different emotions in which normal sorrow and sadness are situated at one end and more severe depressive responses at the other end [72].

Conversely, several prominent members of the psychiatric and medical community have voiced their criticisms about these changes. In fact, quite a debate has ensued around the narrower and broader levels of both the research studies that support the removal of the bereavement exclusion as well as the consequences for the new criteria. There are three major criticisms of the removal of the bereavement exclusion in the DSM-5. First, longitudinal data indicate that those who experienced a single, brief depressive episode due to bereavement had unique symptoms and no greater risk for future depression compared to those who experience other types of depression [52]. Similarly, a comparison of bereavement-related depression and depression from other sources revealed that there are distinct differences between uncomplicated and complicated depression for both bereavement and other losses [73]. These two studies support the previous criteria in the DSM-IV of the bereavement exclusion as a way to distinguish between different types of depression and thus do not support the elimination of the bereavement exclusion in the DSM-5. Second, there have also been important criticisms of the studies cited as evidence for the bereavement exclusion changes in the DSM-5. Some research compared all bereavement-related depression to depressions caused from other life stressors [64]. Critics of the changes considered this type of comparison problematic because they believed there needed to be a distinction between uncomplicated and complicated reactions to grief in the bereavement-related depression group because the bereavement exclusion did in fact distinguish between the two categories [74]. In addition, the international studies by Kessing et al. [70], Corruble et al. [68], and Karam et al. [69] that were previously mentioned were also criticized because they were believed to have either not correctly tested the bereavement exclusion or used samples that were too small to draw any worthy conclusions [74]. The third major criticism to the removal of the bereavement exclusion is that the bereavement exclusion already considered severe expressions of grief. About 10–15% of bereaved individuals reportedly experience severe expressions of grief [75]. It is these individuals to which the new DSM targets [66]; many proponents of the changes argue that the DSM-5 will allow health professionals to identify bereaved individuals who need help. Yet, the criteria to help these individuals who experience severe grief already existed in the DSM-IV [76].

The major arguments for retaining or eliminating the exclusion suggest that although the distinction between severe “normal” grief and depressive illness can be blurry, the two “sides” of the argument would actually treat patients in a very similar manner. Patients seen as experiencing normal grief might be treated for symptoms like insomnia but would be given reassurance that their painful state was “normal” and would resolve over time, while patients seen as suffering from depressive illness would be treated with psychotherapy, medication, or a combination thereof [77] .