The Necessity, Validity, and Clinical Utility of a New Diagnostic Entity: Acute Suicidal Affective Disturbance (ASAD)

Abstract

Objective:

Here we argue for the necessity, validity, and clinical utility of a new diagnostic entity, Acute Suicidal Affective Disturbance (ASAD).

Method:

We expand on the conceptual, clinical, and practical rationale for ASAD, propose its defining features, describe research results to date, and suggest avenues for future research.

Results:

There is accruing evidence for the existence of a previously unclassified, rapid-onset mood disturbance that geometrically escalates and regularly results in life-threatening behavior.

Conclusions:

ASAD research may not only improve the field’s understanding of suicidal behavior, but also enhance clinical effectiveness and save lives.

“The first step in wisdom is to know the things themselves… objects are distinguished and known by classifying them methodically and giving them appropriate names.” Carolius Linnaeus.

Consider the following scenario, based on actual cases encountered by the senior author: an individual is diagnosed with a non-mood disorder psychiatric condition (e.g., schizophrenia) and admitted to inpatient psychiatry. During hospitalization, mood disorder symptoms and suicide risk are regularly assessed and viewed as minimal. The patient’s chart indicated the occurrence of a suicide attempt approximately four years before; however, the circumstances surrounding this attempt were not documented, and unbeknownst to unit clinicians and unreported by the patient, a past history of rapid-onset, intense suicidal crises occurred about five years previously. The condition is aggressively treated, and clear improvement is observed. The individual is thus discharged; approximately 18 hours post-discharge, suicidality again intensifies dramatically, culminating in the individual’s death by suicide. The primary condition had not worsened.

Scenarios like this involving precipitous increases in suicidality (whether occurring post-hospitalization or not) in non-mood disordered patients, although not the norm, nevertheless represent a sizable minority of suicide deaths. Is it plausible to attribute a catastrophic outcome like suicide to a condition that had improved, and that had not subsequently worsened? Is it possible that an ongoing mood disorder was to blame, when mood pathology had been routinely assessed and ruled out? Is it reasonable to leave undiagnosed a condition that leads to death?

Here, we contend that the answer to these questions is “no,” and argue for the necessity, validity, and clinical utility of a new suicide-specific diagnostic entity, Acute Suicidal Affective Disturbance (ASAD; Tucker, Michaels, Rogers, Wingate, & Joiner, 2016; cf. Aleman & Denys, 2014; American Psychiatric Association [APA], 2013). Should clinicians in the case example above have been aware of the possible presence of ASAD—in addition to the patient’s documented suicide attempt history—they may have been alert to the possibility of a rapid recurrence post-discharge and thus, might have intensified safety measures that may have mitigated suicide risk to a non-lethal level. Importantly, entry of a new entity into prominent nomenclatures is unlikely, absent both pressing clinical need and a robust scientific basis. Below we expand on the conceptual, clinical, and practical rationale for a new diagnostic entity, propose defining features, compare ASAD to other proposed suicide-specific entities, describe research results to date, and highlight areas in need of future research.

Conceptual, Clinical, and Practical Rationale for a New Diagnostic Entity

Although suicidality is included at the symptom level in major depressive episodes and borderline personality disorder, these disorders are not defined by it and, moreover, relatively rarely result in death by suicide by themselves. For instance, suicide rates are estimated to range from 3.8–7.8% for mood disorders (Nordentoft, Mortensen, & Pedersen, 2011), and 8–10% for borderline personality disorder (Paris, 2002). Anorexia nervosa and schizophrenia, on the other hand, do not include suicidality as a diagnostic consideration at all, despite being two of the five most lethal psychiatric conditions (i.e., highest death by suicide rate) per capita (see Chesney, Goodwin, & Fazel, 2014). Thus, suicide does not appear to be central to existing conditions—odd, it could be argued, given the lethal outcome.

This state of affairs leaves only two options: (1) the status quo, in which catastrophic outcomes are left diagnostically unexplained—a rarity in healthcare when an illness of some sort is clearly involved (unlike in accidents, for example); or (2) the designation of a suicide-specific diagnostic entity. To address this concern, Suicidal Behavior Disorder (SBD) was included as a “Condition for Further Study” in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association, 2013). The criteria for SBD essentially equate to a suicide attempt in the past two years; thus, suicidal behavior is viewed as an outcome without characterizing the phenomenology of a suicidal crisis. Knowledge of past suicidal behavior is clinically informative and there are substantial benefits of documenting and classifying suicidal behavior (Oquendo & Baca-Garcia, 2014); however, past suicidal behavior provides little insight into whether and when an individual may attempt suicide in the future (Glenn & Nock, 2014; Ribeiro et al., 2016). A focus on acute suicidal symptoms may provide additional clinical insight into suicide risk assessment and management; the importance of capturing acuity is accentuated by the heightened suicide rates following discharge from inpatient psychiatry (Chung et al., 2017). We assert that a suicide-specific diagnostic entity should reflect not only acuity, but also parsimoniously represent empirically identified warning signs for suicide.

Beyond capturing all relevant psychopathology in a nosology, Oquendo and Baca-Garcia (2014) highlight several compelling arguments for a suicide-specific entity in the DSM. Inclusion in nomenclature provides structure for classification in medical records—clinical settings with standardized suicide risk documentation may already ensure that risk is recorded, but this may not be the practice in less structured environments, where data about suicide risk may be lost or not included during hand-offs and in discharge paperwork (Malone, Szanto, Corbitt, & Mann, 1995). This is particularly important in the case of ASAD, where symptom recurrence may be likely and can lead to death. Many clinicians also tend to rely on assessment of self-injurious thoughts and behaviors to determine current suicide risk; however, relatively few focus on acute configurations of suicide risk (i.e., features signaling imminent risk; Glenn & Nock, 2014); ASAD may help fill that gap. Further, conditions that result in death but lack a diagnostic label may lead to misclassification of cause of death in registries. Finally, despite concerns that a suicide-specific diagnosis may facilitate lawsuits, it may actually enhance patient care and mitigate clinician liability (Joiner, Simpson, Rogers, Stanley, & Galynker, 2018).

Defining Features of ASAD

ASAD is thought to be characterized by drastic spikes in suicidality, and as such, is hypothesized to be a time-limited arousal state that abates over time through appropriate management (e.g., Stanley & Brown, 2012). Based on empirical work on acute suicide risk, prominent theories of suicide, and clinical and consulting experience, we conjecture that the key features of ASAD include:

• (A)A drastic increase in suicidal intent over the course of hours or days (not weeks or months);
• (B)Marked social alienation (e.g., social withdrawal, perceived liability on others) and/or self-alienation (e.g., self-hatred, perceptions that one’s self is an onerous burden);
• (C)Perceptions that the above criteria are hopelessly intractable;
• (D)Two or more manifestations of overarousal (agitation, irritability, insomnia, nightmares).

Further, the disturbance cannot be wholly accounted for by another condition, such as a mood disorder or substance use. Individuals who experience all four criteria within a time-frame of hours or days are considered to meet criteria for an ASAD diagnosis; those experiencing these symptoms in the past week meet criteria for a current ASAD episode.

Theoretical Context.

Suicidal Intent.

Suicidal intent, characterized by explicit intentions and plans to make a suicide attempt, has been associated with an increased likelihood of death by suicide (Nock & Kessler, 2006). Importantly, suicidal intent and desire are not synonymous and vary independently of one another (Van Orden et al., 2010); indeed, suicidal intent and resolved plans and preparations signal more imminent risk for suicide than suicidal desire (Joiner et al., 2003). Although little research has explicitly examined the trajectory of suicidal intent over time, there is evidence to suggest that, at least in some individuals, suicidal intent may rapidly escalate over time. For instance, individuals discharging from inpatient psychiatric units, who presumably have been thoroughly assessed for suicide risk prior to discharge, have considerably high suicide rates, particularly in the days and weeks following discharge (Chung et al., 2017). One possibility is that these decedents failed to disclose continuing suicidal thoughts and urges; another is that suicidal intent returned rapidly following discharge. Another line of research suggests that some individuals engage in suicidal actions without spending much time contemplating or planning for suicide (Rimkeviciene, O׳Gorman, & De Leo, 2015). One study examining the hours preceding suicidal behavior found that 42% progressed from first contemplation of suicide to a suicide attempt within 3 hours; likewise, 68% progressed from first consideration of a plan, and 85% made the decision to act, within this timeframe (Bagge, Littlefield, & Lee, 2013). Although these individuals are often described as “impulsive” suicide attempters (May & Klonsky, 2016), associations between suicidal behavior and impulsivity are small (Anestis, Soberay, Gutierrez, Hernandez, & Joiner, 2014; May & Klonsky, 2016). Another possibility is that some of these individuals are experiencing rapidly intensifying increases in suicidal intent that culminate in suicidal behavior.

Social Alienation.

Social isolation, comprising loneliness, social withdrawal, and a lack of social support among other facets, is one of the most reliably documented predictors of suicidal ideation, attempts, and death by suicide across samples with varying ages, nationalities, and clinical features (e.g., Duberstein et al., 2004). Psychological autopsy studies have demonstrated that in the days and weeks leading up to an individual’s death by suicide, suicide decedents frequently become more socially withdrawn, less talkative, and lose interest in social activities (Appleby, Cooper, Amos, & Faragher, 1999). Likewise, in-person proximity to others has been associated with changes in suicidal ideation in real-time (Husky et al., 2017). The three-step theory (Klonsky & May, 2015) specifically posits that social connectedness may serve as a protective factor against active suicidal desire. Similarly, the interpersonal theory of suicide (Van Orden et al., 2010) conceptualizes thwarted belongingness (loneliness and a perceived absence of reciprocal relationships) and perceived burdensomeness (the belief that one’s death is worth more than one’s life) as multidimensional latent constructs that characterize internal perceptions of social disconnectedness and lead to suicidal desire. Each of these constructs has accumulated support as a correlate of suicidal thoughts and behaviors (see Chu et al., 2017, for meta-analysis). Altogether, social isolation—whether in the form of actual withdrawal from others or perceived social connection—is a pernicious risk factor for suicide.

Self-Alienation.

Major conceptualizations of suicide highlight some form of intractable agony. For instance, theories on psychache (Shneidman, 1996), hopelessness (Beck, Steer, Kovacs, & Garrison, 1985), escape (Baumeister, 1990), and the three-step theory (Klonsky & May, 2015) emphasize intractability and psychological pain; however, the specifics of agony are not described in detail. Indeed, Klonsky and May (2015) argue that pain may arise from myriad sources, rather than any one type of aversive thought, emotion, or experience. The integrated motivational-volitional model of suicidal behavior (O’Connor, 2011) and the interpersonal theory of suicide (Van Orden et al., 2010) specifically describe the nature of psychological suffering (i.e., defeat, entrapment, thwarted belongingness, perceived burdensomeness). Likewise, some have identified acute, high-intensity states of negative affect serving as a trigger for suicidal behavior (Hendin, Al Jurdi, Houck, Hughes, & Turner, 2010).

In addition to psychological pain, ample literature has pointed to self-disgust, self-hatred, and inwardly-directed hostility as indicators of suicide risk. Self-disgust elicits a desire to withdraw from one’s revulsive attributes and feelings of negativity or hatred toward the self; it may also trigger an active desire to physically avoid or destroy the object of revulsion (in this case, the self; Moll et al., 2005). Disgust with the self has also been linked to a variety of negative self-views, including self-hatred and self-criticism (Gilbert, Clarke, Hempel, Miles, & Irons, 2004; Powell, Overton, & Simpson, 2014), each of which have been robustly associated with self-injurious thoughts and behaviors (Hendin, Maltsberger, Haas, Szanto, & Rabinowicz, 2004). Self-hatred, composed of low self-esteem, self-blame/shame, and agitation, is also a defining feature of perceived burdensomeness (Van Orden et al., 2010); accordingly, repulsion or hatred of the self may contribute to feelings of perceived burdensomeness and suicidality.

Hopelessness.

Hopelessness is an oft-cited risk factor for suicidal ideation, attempts, and death by suicide, and has been included in several theoretical accounts of suicide, including Beck’s hopelessness theory (Beck et al., 1985) the interpersonal theory of suicide (Van Orden et al., 2010), and the three-step theory (Klonsky & May, 2015). Together, these theories converge to support the idea that perceived intractability of psychological pain, social alienation, and self-alienation may contribute to, at minimum, desire for suicide.

Overarousal.

Empirical support also exists for overarousal states, including agitation (Busch, Fawcett, & Jacobs, 2003), irritability (Trivedi et al., 2011), and sleep disturbances (Pigeon, Pinquart, & Conner, 2012), preceding suicidal behavior. Agitation has been observed among suicide decedents in the week prior to their deaths (Busch et al., 2003) and has predicted death by suicide within a one-year follow-up period (Fawcett et al., 1990). Similarly, irritability has been linked to increased suicide risk (Trivedi et al., 2011), especially among those who are experiencing mixed episodes (Popovic et al., 2015). Sleep disturbances are also frequently observed in suicide decedents prior to their deaths (Busch et al., 2003) and have predicted suicidal ideation, attempts, and death by suicide at one-year follow-up (Fawcett et al., 1990; Wojnar et al., 2009). Overarousal may precede suicidal actions because killing is a daunting act that cannot be enacted without high states of energy and arousal (Joiner & Stanley, 2016); suicide involves dying too, and the prospect of death is fearsome and alarming, thus activating and arousing (Joiner, Hom, Hagan, & Silva, 2016). Indeed, this proposition has been supported across several studies examining interactions between overarousal and capability for suicide in predicting suicide risk and behaviors (Ribeiro, Silva, & Joiner, 2014; Ribeiro, Yen, Joiner, & Siegler, 2015).

Overall, ASAD criteria capture the intersection of these theories well and may represent a distinct class of individuals whose affective disturbances result in a deadly spike of suicidality. Below we describe research findings to date, as well as a program of research that will be necessary to further support or falsify these claims.

Research to Date on the Construct Validity of ASAD

The structure of ASAD has been examined in samples of at-risk young adults (Tucker et al., 2016) and psychiatric outpatients and inpatients (Rogers, Chiurliza, et al., 2017; I. H. Stanley, Rufino, Rogers, Ellis, & Joiner, 2016); these studies support the unidimensionality and cohesion of ASAD symptoms. For instance, Tucker et al. (2016) first examined ASAD in undergraduate students with a history of suicidality, using an instrument specifically designed to measure worst-point ASAD symptoms. In this study, ASAD demonstrated a strong one-factor solution; Stanley et al. (2016) and Rogers et al. (2017) replicated and extended these findings considerably in large samples of psychiatric outpatients and inpatients, through the use of proxy items and measures that tap into the ASAD construct and the use of confirmatory factor analyses. These samples similarly yielded evidence of convergent and discriminant validity, with expected and non-redundant associations between ASAD and other risk factors, personality correlates, and existing psychological disorders (Rogers et al., 2016; Rogers, Chiurliza, et al., 2017). Finally, ASAD symptom severity differentiated individuals who have attempted suicide from those who have thought about suicide across all samples, and was associated with lifetime suicide attempts beyond depression symptoms and other psychiatric disorders (Rogers, Chiurliza, et al., 2017).

Likewise, in an initial effort to examine the cohesion of ASAD as well as its divergence from symptoms of anxiety and depression, Rogers, Hom, and Joiner (under review) conducted a network analysis in a sample of psychiatric inpatients to evaluate whether current ASAD symptoms comprised a psychopathological network distinct from current anxiety and depression symptoms. Network analyses revealed three distinct clusters of symptoms, corresponding to ASAD, anxiety, and depression symptoms. Of note, ASAD symptoms demonstrated not only strong associations with each other, but relatively weaker associations with symptoms of anxiety and depression, supporting their distinctiveness. Though preliminary due to reliance on a cross-sectional design, these findings indicate that ASAD may represent a construct distinct from anxiety and depression despite similar symptom criteria (e.g., agitation, sleep disturbances), underscoring its potential diagnostic value and the possibility that symptoms manifest differently within the context of ASAD episodes than in other forms of psychopathology. Together, initial studies support the construct validity of ASAD, though with some crucial limitations.

Other Proposed Suicide-Specific Diagnostic Entities

As noted previously, other independently-developed suicide-specific diagnostic entities have been developed; however, each differs conceptually from ASAD. First, we have already discussed differences between ASAD and SBD, such that ASAD captures the acute phenomenology of a suicidal crisis, whereas SBD denotes the occurrence of a suicide attempt within the preceding two years. On the other hand, Suicide Crisis Syndrome (SCS; Galynker et al., 2017) and ASAD have several overlapping criteria, including an acute and rapid-onset course of relatively short duration, and aspects of overarousal, hopelessness, and social withdrawal (see Rogers, Galynker, Yaseen, Defazio, & Joiner, 2017, for a detailed comparison). However, a critical distinction between the two conditions lies in the centrality of suicidal ideation/intent. Specifically, suicidal intent is a core feature of ASAD, but explicit suicidal ideation is not required in SCS. An intriguing possibility is that SCS and ASAD represent the same illness, though at different points in the course of illness of over time, with ASAD representing the end-stage. Future work should compare the nature of these conditions, especially in understanding distinctions between ASAD, SBD, and SCS (and indeed, whether the latter and ASAD are characterizations of the same overarching condition).

Future Areas of Research

Future work validating a suicide-specific diagnostic entity is needed in several domains. In a classic paper, Robins and Guze (1970) emphasized five criteria necessary for validation of psychopathological diagnostic entities: clinical description (defining features, prevalence, course, and precipitating factors), laboratory study (physiological, anatomical, and psychological test findings), exclusion of other disorders (differentiation from already-existing conditions), study of course of illness (allowing for understanding of ASAD over time), and family history research (examination of hereditary and environmental contributions). Further, antecedent, concurrent, and predictive validation must be present (Regier, Kuhl, & Kupfer, 2013).

Clinical Description.

First, although most studies to date have examined ASAD’s clinical presentation, additional studies investigating the typical onset and time-course of ASAD (particularly as it pertains to the interrelatedness of ASAD symptoms), precipitating biopsychosocial factors, and differences across sociodemographic groups are needed. For instance, some evidence suggests that negative thought patterns and suicide-specific rumination may contribute to the occurrence and increased likelihood of recurrence of an ASAD episode (Rogers & Joiner, 2018; Rogers et al., 2018). It may also be worth examining whether ASAD features differ, dependent on whether suicidal desires are expressed in an operant (i.e., functioning to affect the environment) or respondent (i.e., elicited by preceding events or situations) manner (Linehan, 1993)—or conversely, whether desires are expressed at all. Additionally, some features of ASAD (e.g., social alienation) have been examined using experimental methods; these studies have revealed interactions between social alienation and capability for suicide in predicting laboratory proxies for self-injurious behavior (Hames et al., 2017). Ethical experimental designs assessing other ASAD components (e.g., self-alienation, overarousal) may further clarify the clinical picture. Similarly, it will be important to differentiate rapid surges of suicidal intent leading to suicidal behavior from impulsive behavior more generally, consistent with evidence that suicide is not linked directly to impulsivity (Anestis et al., 2014). It will also be worth establishing that ASAD represents a surge in suicidal intent rather than simply increased disclosure of already-present intent, given that suicidality may be underreported in some high-risk populations (e.g., Vannoy et al., 2016), and that issues related to accurate disclosure of suicidal intent are critical to the clinical utility of ASAD. In particular, the use of implicit measures, behavioral observations, and/or discussions with close others (e.g., family members) to assess suicide risk, or the use of supplemental, less face valid, assessments of ASAD (pending the determination of such features in future research) may be beneficial.

Laboratory Study.

Biological studies at all levels of analysis may also be informative. Consistent and reliable findings regarding the biological correlates of suicide risk and many psychiatric disorders have been elusive (Ernst, Mechawar, & Turecki, 2009). Nevertheless, when consistent with a defined clinical picture, laboratory studies add considerable value. For example, a review of neuropsychological and neuroimaging studies found that (1) suicide attempters showed greater attention to specific negative emotional stimuli, impaired decision-making and problem-solving, and reduced verbal fluency; and (2) the ventrolateral orbital, dorsomedial and dorsolateral prefrontal cortices (dPFC), anterior cingulate gyrus, and the amygdala may play a role in facilitating the development of suicidal crises and actions (Jollant, Lawrence, Olié, Guillaume, & Courtet, 2011). More specifically, recent studies examining the potential pathophysiological substrates of suicide have found evidence for disrupted activation and neuronal impairments (i.e., low metabolic N-acetylaspartate; Jollant, Near, Turecki, & Richard-Devantoy, 2017) in the right dPFC of individuals with a history of suicide attempts (Jollant et al., 2008; Sublette et al., 2013). Among individuals who have attempted suicide, disrupted dPFC functioning and connectivity with other cortical regions may be associated with altered sensitivity to social environment and impaired decision-making, difficulties regulating negative emotions and solving problems, and facilitation of behaviors in an emotional context (Jollant et al., 2017). Consistent with behavioral manifestations of ASAD, these dPFC-related impairments may contribute to increased social- and self-alienation and perceptions that feelings of pain and alienation are intractable. Notably, these studies suggest the potential for examination of biologically driven processes associated with ASAD.

Delimitation from Other Disorders.

Since similar clinical features are often shared across disorders (APA, 2013), further research must ensure that the key ASAD features are not better accounted for by other conditions. ASAD is not viewed as a consequence of worsening mood symptoms or substance use. Indeed, some preliminary evidence, as noted above, suggests that ASAD is distinct from various disorders (Rogers, Chiurliza, et al., 2017), and symptoms of anxiety and depression (Rogers et al., under review). Future work, however, is needed to replicate and extend these findings in distinct samples from separate groups of investigators, as well as examining associations between ASAD and other symptom clusters (e.g., posttraumatic stress disorder, borderline personality disorder, substance use disorders) to establish ASAD’s distinct contributions.

Course of Illness.

All studies thus far have been cross-sectional, precluding examination of etiology and course. Prospective studies of ASAD are essential not only given the time-limited nature of ASAD, the likelihood that episodes may recur, and limited data to date on prognosis, but also to determine if patients are suffering from some other already-defined disorder that could better account for the original clinical picture (coinciding with our discussion of Delimitation from Other Disorders, above). Repeated follow-up assessments and methodologies, such as ecological momentary assessment (Kleiman & Nock, 2017) or timeline follow-back methodology (Bagge et al., 2013), are well-suited for short-term prospective studies on ASAD. Further, subsequent to the identification of patients who have experienced an ASAD episode, long-term follow-up should examine the course and prognosis of ASAD.

Family Study.

Finally, although suicide is known to be more prevalent among family members of suicide decedents (Qin, Agerbo, & Mortensen, 2002), ASAD has not been examined using familial frameworks. Future research examining the occurrence of ASAD among close relatives to better understand hereditary and environmental contributions to suicidal behavior is needed. Importantly, this area of research need not be separate from the other phases of establishing diagnostic validity; these phases should interact with one another to provide further refinement of ASAD.

Categorical versus Dimensional Approaches to Psychopathology

None of the foregoing provides definitive evidence for ASAD, though evidence is accruing that it is a valid and relevant entity. However, it could be argued that the addition of ASAD to the nomenclature stands in contrast to dimensional approaches to psychopathology (e.g., Hierarchical Taxonomy of Psychopathology [HiTOP]). Traditional taxonomies, like the DSM, characterize psychopathology categorically rather than as on a continuum; this approach may exhibit limited reliability, high heterogeneity, and high rates of comorbidity between disorders (Kotov et al., 2017). It should be noted, however, that even if death by suicide and, for example, moderate suicidal ideation represent differing locations on the same underlying continuum, death is categorical, and thus there may be pragmatic benefits in characterizing the lethal or near-lethal area of the continuum as having its own distinctiveness. Moreover, it is surely possible that the suicidality spectrum is a hybrid of the categorical and dimensional, with a true break occurring at the extreme severe end of the spectrum and with continua operative with each side of the break; Waller and Meehl (1998) repeatedly noted their view that this was the case with all or almost all phenomena in nature that display categorical qualities.

Nevertheless, given these new directions in the field, it is worth exploring ASAD symptoms dimensionally as a spectrum of co-occurring symptoms, rather than as a diagnostic category. For instance, future studies investigating the nature and diagnostic relevance of ASAD would benefit from the use of multiple indicators across different units of analysis and incorporating constructs from the NIMH’s Research Domain Criteria (RDoC) endeavor (Simmons & Quinn, 2014). Indeed, several RDoC domains (e.g., negative and positive valence, perception and understanding of others, arousal systems) have been examined in relation to suicide risk more generally (see Glenn, Cha, Kleiman, & Nock, 2017, for review), with statistically significant, yet small, weighted effect sizes (Glenn et al., 2018). Moreover, several components of ASAD overlap with the negative valence, cognitive, social processes, and arousal and regulatory systems. In order to emerge as a practical alternative to DSM-based diagnoses, though, others have argued that these systems will need to prove (a) reasonable applicability in ordinary clinical practice and among different categories of professionals; and (b) to be more clinically useful in guiding treatment decisions and predicting outcomes (Maj, 2018), evidence that has not yet accrued.

With regard to the study of suicide, at least three distinct research teams have independently identified subgroups at serious risk of suicide; these subgroups tend to be characterized by ASAD symptoms. In addition to our team’s research on ASAD and separate research on SCS (Galynker et al., 2017), the Army STARRs project (Schoenbaum et al., 2014) and Witte et al. (2017) have reported on severe subgroups that would likely satisfy ASAD criteria. In the latter example, there is evidence for a categorically distinct subgroup. The taxon’s two primary indicators were suicidal intent and insomnia, which overlap considerably with ASAD criteria. Accordingly, categorical/taxometric and dimensional approaches are likely complementary, and future research utilizing both categorical and dimensional approaches to understanding suicide, as well as suicide-specific entities, like ASAD, is worthwhile.

Conclusion

This paper’s epigraph references Linnaeus, but we do not claim that the ASAD conjecture is Linnaean in profundity or scope. Although much research is needed to validate ASAD as a distinct clinical entity, we believe that ASAD is discernable from and non-redundant with existing clinical entities, and that it is clinically useful. ASAD deserves consideration in future versions of prominent nosologies and, far from encouraging continued prejudice and stigma, it will further understanding and prevention of states of mind that culminate in death by suicide.