Cognitive/Neuropsychological Functioning and Suicidal Behavior: A Review of Research and Implications for Clinical Practice

CATEGORY 1 CME

Premiere Date: November 20, 2021

Expiration Date: May 20, 2023

ACTIVITY GOAL

Identify 3 patient groups who are characterized by elevated rates of suicidal behavior and co-occurring cognitive/neuropsychological impairment.

LEARNING OBJECTIVES

1. Increase familiarity with the indications for psychological/neuropsychological testing of patients with suicidal behavior and suspected or known cognitive/neuropsychological impairment.

2. Enhance an appreciation of a good working knowledge of neurocognitive status in assessment and treatment planning with suicidal patients.

TARGET AUDIENCE

This accredited continuing education (CE) activity is intended for psychiatrists, psychologists, primary care physicians, physician assistants, nurse practitioners, and other health care professionals who seek to improve their care for patients with mental health disorders.

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Physicians’ Education Resource®, LLC, designates this enduring material for a maximum of 1.5 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

This activity is funded entirely by Physicians’ Education Resource®, LLC. No commercial support was received.

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Suicidal behavior is a complex and incompletely understood biopsychosocial syndrome. It encompasses suicidal thinking (sometimes accompanied by plan and/or intent), attempted suicide, and death from suicide. Despite intensive study over decades, suicidal behavior eludes reliable prevention and prediction and, for many patients, is not a well-treated set of conditions.¹

In recent years the evidence base regarding suicide etiology, prevention, assessment, and intervention have all expanded, and a number of promising prevention and treatment innovations for suicidal behavior have been developed.² Still, rates of completed suicide continue to increase among nearly all age groups.³ Since at least the start of this century, death from suicide has become a well-entrenched public health epidemic with no signs of abating.

During the second half of the 20th century, clinical and research studies on suicide were largely focused on the psychosocial and psychodynamic underpinnings of suicidal behavior (a working definition of suicidal behavior appears in Table 1). By way of contrast, scant attention was paid to possible neurobiological correlates and causal factors.

Table 1. Suicidal Behaviors

The idea that suicidal behavior might have its genesis, in part, in neurobiology may have emerged as early as the 1960s.⁴ However, the study of the interface of neurobiology and what are referred to as neuropsychiatric disorders in contemporary clinical practice began in earnest only in the 1980s. This helped to galvanize research on cognitive/neuropsychological dysfunction as a possible significant risk factor for suicidal behavior and, hence, its importance as a potential target for assessment and intervention. Research findings since the early 2000s have outlined cognitive/neuropsychological correlates of suicidal behavior, with an emphasis on the role that cognitive/neuropsychological impairment may play as both a potential diathesis and stressor with respect to susceptibility to suicidal behavior.

This research can help clinicians in the realms of assessment and intervention. For clinical assessment of risk of suicidal behavior, options include the Stress-Diathesis and Risk-Protective Factors models. According to recent studies, 3 broad clinical groups are characterized by high base rates for both cognitive/neuropsychological impairment and suicidal behavior. Therefore, a good working knowledge of a patient’s neurocognitive status can help guide clinical assessment and intervention. Future research could clarify the relationship between cognitive/neuropsychological impairment and suicide, hopefully leading to advances in suicide prevention.

Stress-Diathesis and Risk-Protective Factors Models

The Stress-Diathesis model conceptualizes suicidal behavior as multi-determined and the outcome of preexisting distal vulnerabilities (diathesis) interacting with recent and current proximal situational stressors/triggers.⁵ The latter can contribute to the probability and timing as well as the pattern and relative severity of suicidal behavior in the individual case.^6,7

Predisposing vulnerabilities include a blend of neurobiological factors and predisposing influences that are psychosocially/psychodynamically based (Table 2). These factors can, in part, reflect the impact of multiple biological influences (including a history of neurodevelopmental difficulties) but are also thought to be significantly affected by adverse life events and trauma, especially those occurring early in life: mistreatment, neglect, abandonment, and other detrimental life experiences.^8-10

Table 2. Neurobiological and Psychosocial Risk Factors

For many patients, the interaction of these biopsychosocial factors results in serious problems with the development of age appropriate behavioral and emotional self-regulation abilities and skills, as well as more general difficulties with adaptation through the lifespan. This includes noteworthy problems coping with adversity, especially attachment and loss issues associated with situational stressors and lifespan developmental transitions.

The interplay of a patient’s diathesis and situational stressors/triggers of varied type (which are commonly experienced by patients as existential threats to their psychological and/or physical well-being) can significantly heighten the risk for suicidal behavior.^8,11 The degree/severity of risk is attenuated, to some extent, by protective factors: patient’s personality assets, good social support, access to psychiatric care, and other favorable life circumstances.

The Stress-Diathesis model aligns reasonably well with the Risk-Protective Factors model both conceptually and in terms of its heuristic value for clinical assessment and intervention. This conceptual framework emphasizes the importance of the interaction of distal and proximal influences that augment vulnerability (risk factors) and influences, which reduce susceptibility to suicidal behavior (protective factors). This paradigm is employed to create an overall suicidal risk profile for patients who are seen for clinical assessment.¹¹

Identifying 3 At-Risk Clinical Groups

Three clinical groups are at significant risk for a combination of cognitive/neuropsychological impairment and suicidal behavior: individuals with neurodevelopmental disorders, neuropsychiatric disorders, and acquired cognitive or neuropsychological disorders. Details on each of these conditions appear in Table 3.^12-23

Table 3. Clinical Groups at Significant Risk for Suicidal Behavior

Patients who fall into 1 or more of these 3 groups grapple with a number of challenges that can negatively impact psychosocial development, executive functioning, and quality of life. They can struggle with identity formation/consolidation, self-esteem regulation, psychological and cognitive insight, judgment, social cognition, cognitive flexibility, impulse control/response inhibition, task initiation, organization/planning, decision-making, and problem solving.

Additional difficulties often involve 1 or more components of negative affectivity, including anger, irritability, lability, anxiety, and depression. Some patients report intolerable recurrent or chronic emotional and psychological pain together with a proclivity to overreact or emotionally shut down in response to acute and chronic stressors.⁹ This construct has considerable overlap with the term neuroticism, which is a key component of the 5-factor dimensional personality model and has applicability to DSM-5 personality disorders.²⁴

A substantial number of patients who fall into 1 or more of these 3 groups have at least mildly reduced ability to profit from experience. They may have trouble learning and successfully using coping skills for the purpose of distress tolerance, stress reduction, and responding in a flexible manner to problematic life events. Overall, these patients have significant difficulty building resilience in the face of lifespan developmental challenges and demands. Their struggles in this regard are often complicated by high rates of co-occurring mental health and substance abuse disorders.

The plethora of cognitive and emotional challenges that these patients confront on a daily basis contribute to a significant vulnerability to recurrent as well as persistent behavioral-mood instability.

The plethora of cognitive and emotional challenges that these patients confront on a daily basis contribute to a significant vulnerability to recurrent as well as persistent behavioral-mood instability. Patients who fall into 1 or more of these groups have elevated rates of suicidal behavior.

NEURODEVELOPMENTAL.^25-27 There is a nearly 5 times higher rate of suicidal behavior than among patients with attention-deficit/hyperactivity disorder.²⁵ For individuals with autism spectrum disorder, rates of suicidal behavior range from 7% to 47%.²⁶

NEUROPSYCHIATRIC.^28-37 For schizophrenia and other psychotic disorders, the lifetime risk for 1 or more suicide attempts ranges from 25% to 50% percent, and lifetime risk of completed suicide ranges from 4% to 10%.²⁹ Over their lifetimes, individuals with bipolar disorder have a 15% to 50% risk of making 1 or more suicide attempts.³¹ Among patients who have made 1 or more suicide attempts, more than 70% had histories of anxiety disorder.³⁴ Patients with major depressive disorder have a lifetime risk of completed suicide ranging between 2% and 15%.³⁷ Among those with borderline personality disorder, the lifetime risk for 1 of more suicide attempts ranges from 50% to 90%; lifetime risk for completed suicide is up to 10%.⁶

ACQUIRED COGNITIVE/NEUROLOGIC.^20,21,38-40 Among patients newly diagnosed with Alzheimer disease and related dementias, the Standardized Mortality Ratio/SMR for completed suicide was 1.53 with a 95% confidence interval of 1.42 to 1.65; however, among newly diagnosed patients aged between 65 and 74 years, the Standardized Mortality Ratio/SMR for completed suicide was 3.40 with a 95% confidence interval of 2.94 and 3.86.³⁸ Reports of lifetime completed suicide rates for individuals with epilepsy range from 1% to 33%.³⁹ Patients with traumatic brain injury have a 2- to 4-fold greater risk of completed suicide than the general population.⁴⁰

Research on Cognitive/Neuropsychological Functioning

A number of studies include investigations of the cognitive/neuropsychological functioning of patients with neurodevelopmental, neuropsychiatric, and neurologic/medical diagnoses that are associated with elevated rates of suicidal behavior.^20,26,41 The majority of these involve adult patients with neuropsychiatric disorders, notably major mood disorders and schizophrenic spectrum disorders.

Some studies have focused on the relationships between cognitive/neuropsychological functioning and suicidal thinking while others have examined the relationship of cognitive/neuropsychological functioning and suicidal behavior in the form of 1 or more suicide attempts, or a history of suicidality broadly defined to include suicidal thinking and attempts.

Several studies have found positive relationships between cognitive/neuropsychological impairment and suicidal thinking. For example, a study that employed a general population sample and a subgroup with depressive disorders found that a significant positive association between cognitive/neuropsychological impairment and suicidal thinking, including a strong link with higher frequency suicidal thinking.⁴² An investigation that assessed the cognitive/neuropsychological integrity of patients with major depressive disorder, with and without suicidal thinking, found that scores on measures of motor speed and executive functioning were significantly lower among patients with suicidal thinking.⁴³ Moreover, greater compromise in cognitive/neuropsychological functioning was correlated with more severe suicidal thinking.

Other studies have compared the cognitive/neuropsychological test performance of psychiatric patients with histories of suicidal behavior (defined as 1 or more serious suicide attempts), with psychiatric controls—patients with comparable mental health difficulties but with negative histories of suicidal behavior, as well as participants with negative mental health histories (ie, healthy controls).⁴⁴

Meta-analytic reviews of the literature comparing these 3 groups highlight an array of cognitive/neuropsychological difficulties in patients with 1 or more mental health condition(s) and histories of suicide attempts, when compared with psychiatric and nonpsychiatric controls. Such difficulties include worse performance on tests of decision-making, category fluency, and response inhibition in patients with depressive and bipolar mood disorders; they also include lower performance on tests of long-term memory and working memory in patients with depressive and bipolar disorders, schizophrenia, schizoaffective disorder, and other conditions like borderline personality disorder.^45,46

A recent literature review compared patients with diagnoses of schizophrenia, schizoaffective disorder, and major mood disorder (major depression, bipolar I, and bipolar II disorder) and a history of suicide attempts with patients with similar diagnoses but without suicide attempts. The comparison was based on a series of cognitive/neuropsychological tests, many of which can be considered measures of executive functioning.⁴⁴

Patients with histories of 1 or more suicide attempts performed worse than those with comparable neuropsychiatric diagnoses who did not attempt suicide. Findings were mixed, however, with respect to performance on tests of decision-making and constructional praxis. Moreover, measures of working memory did not clearly discriminate between these 2 groups.⁴⁴

Another literature review compared patients across a broad range of neuropsychiatric diagnoses with suicidal thinking with patients who had a history of attempts as well as patients with negative histories for suicidal behavior, looking at various neurocognitive measures.⁴⁷ Differences between patients with suicidal thinking and those who actually attempted suicide were characterized as “negligible to small.” There were, however, medium size effects between these groups for performance on 2 measures of executive functioning. Those participants who had attempted suicide performed worse in decision-making and inhibition. There were no significant effect size differences on any neurocognitive measures or indices between patients with suicidal thinking and patients without histories of suicidal behavior. The only exception was a large effect size on measures of information processing speed, in favor of the latter group.

A review of the literature that focused on performance on a wide range of tests of executive functioning in relation to suicidal thinking and/or attempted suicide across a number of neuropsychiatric diagnoses found “some evidence” and “tentative support” for links between impaired executive functioning and suicidal behavior. Associations appeared stronger for patients with depressive disorders than with patients with bipolar or psychotic disorders.⁴⁸

Discussing the Findings

The findings of these and other reviews offer modest support for the idea that psychiatric patients with histories of suicidal behavior have more problematic cognitive/neuropsychological functioning than non-suicidal psychiatric patients.^49,50 Moreover, these difficulties with neurocognition may be conceptualized, at least in part, as trait markers, that are relatively separate and distinct from the impact of state-related affective/behavioral factors and co-occurring mental disorders, including depression, on a patient’s cognitive/neuropsychological status.⁵¹

That said, other studies have not found meaningful relationships between neurocognitive status and suicidal behavior.³² Although counterintuitive, some studies noted better cognitive/neuropsychological functioning among those patients with schizophrenia who attempted suicide as opposed to those who did not attempt with the same diagnoses.^52-54

It is also important to consider that most medical and/or psychiatric patients with cognitive/neuropsychological impairment have negative histories for suicidal behavior. Substantial numbers of psychiatric patients with histories of suicidal behavior have no apparent problems with their neurocognition.

Indeed, profiles of intact and impaired cognitive/neuropsychological abilities/skills may prove to be more germane to risk for suicidal behavior than impaired abilities/skills per se. For example, the neurocognitive status of a sample of suicidal attempters has been characterized by relatively good problem-solving abilities/skills but relatively poor impulse control/response inhibition.⁵⁵

Lessons Derived From the Literature

To date, there is suggestive but insufficient evidence to reliably support robust and independent cause and effect relationships between cognitive/neuropsychological impairment and elevated rates of suicidal behavior among patients with neurodevelopmental, neuropsychiatric, and/or acquired neurocognitive disorders.

As is true of many factors that may be implicated in complex multifactorial outcomes like suicidal behavior, the possible impact of cognitive/neuropsychological impairment on the susceptibility to suicidal behavior is likely to vary as a function of an individual’s clinical profile of intact and impaired cognitive/neuropsychological abilities. A host of medical, psychosocial, psychodynamic, and situational influences might affect outcomes as well. Neuropsychiatric diagnosis may also be a relevant factor.⁴⁸

Additionally, it may be that the number and relative severity and/or the stage of the neurodevelopmental, neuropsychiatric, and medical/neurologic condition(s)—as well as a patient’s particular nexus of self-harm related risk and protective factors—all play key roles. These are moderator variables, which mediate the impact of cognitive/neuropsychological impairment on the risk for suicidal behavior.

For instance, Alzheimer disease is a risk factor for suicidal behavior, even many years after formal diagnosis. There is some evidence that patients newly diagnosed with mild neurocognitive disorder, possible Alzheimer disease, or cognitive/neuropsychological changes consistent with probable early phase Alzheimer disease may be at greater risk for suicidal self-harm than patients with more advanced illness.^38,56

It may also be the case that at least some of the effects of a patient’s cognitive/neuropsychological status are indirect in so far as they negatively impact other risk factors which, in turn, elevate risk for suicidal behavior.

For example, cognitive/neuropsychological impairment can sometimes result in disinhibition and impulsivity, which lead to reckless behavior or exacerbate preexisting personality trait vulnerabilities. In association with potentially destabilizing influences like substance abuse and other proximal psychosocial stressors/triggers, these difficulties would be expected to significantly raise the risk for suicidal behavior. In this scenario, a patient’s profile of cognitive/neuropsychological abilities and deficits may even facilitate the transition from suicidal thinking to a suicide attempt.

Other cases of cognitive/neuropsychological impairment, characterized by problems with conceptual thinking, language processing, working memory, and/or anterograde memory, would likely differentially impact comprehension and retention. These issues could lead to poor understanding and follow-through with crisis/safety and treatment plans.

In both instances, the patient’s neurocognitive profile may elevate risk for suicidal self-harm and, together with other factors, override the potentially mitigating influence of protective factors.

If cognitive/neuropsychological factors can be more firmly established as an important set of causal influences in augmenting the risk of suicidal behavior, then they should be viewed as one of many significant predisposing risk factors. Accordingly, they would begin to play a more frequent and prominent role in suicide assessment and intervention. This might include the development of relatively brief and well-tolerated neurocognitive screening tests, which could be integrated into formal risk assessments to enhance predictive validity, as well as help guide clinical management and harm reduction strategies.⁵⁷

The Role of Psychological/Neuropsychological Testing

To date, the clinical utility of cognitive/neuropsychological testing for the assessment of suicidal behavior lacks a clear evidentiary base. Therefore, the following discussion is based on clinical experience, while considering the aforementioned findings on links between cognitive/neuropsychological impairment and suicidality.

Cognitive/neuropsychological testing may be appropriate in the context of a history of neurodevelopmental disorder, neuropsychiatric disorder, and/or acquired neurologic disorder, as well as suspicion of possible cognitive/neuropsychological impairment. Indications for cognitive/neuropsychological testing include a history of chronic or recurring suicidal thinking with 1 or more workable plans, intent, and/or evidence of preparation and/or a recent history of 1 or more serious (high risk/low rescue) suicidal attempts.

Cognitive/neuropsychological testing is less clearly indicated for patients with histories of suicidal behavior but who do not clearly fall into 1 or more of the 3 clinical groups previously reviewed. It is also less clearly indicated for patients with negative histories for presumptive neurocognitive impairment, and when there is little to no suspicion of concerning recent/current negative change(s) in neurocognition. However, psychological testing with an emphasis on clarifying the possible temperamental, personality trait, psychosocial, and/or psychodynamic contribution to suicidal behavior should be strongly considered for this subset of patients.

Because many referred individuals have a complex diathesis for suicidal behavior that reflects a mix of both neurobiological and psychosocial factors and situational stressors/triggers that have compelling psychodynamic resonance for the patient, a test battery that includes both psychological and cognitive/neuropsychological assessments is often the best choice given.

In some instances, findings from psychometric tests may highlight the potential value of compensatory strategies to work around cognitive/neuropsychological impairments, thereby enhancing symptom management and harm reduction. In this regard, there soon may be a time when patients who have significant histories of suicidal behavior are concurrently seen for cognitive rehabilitation services. These services could target the neurocognitive impairments that appear to play a role in the recurrence and/or persistence of suicidal thinking and behavior.

Directions for Future Research

A considerable amount remains to be learned about the clinical relevance of links between cognitive/neuropsychological functioning and suicidal behavior.

Research is clearly warranted to further elucidate the putative mechanisms and pathways by which cognitive/neuropsychological impairment may heighten risk for suicidal thinking and attempts. As such, research should investigate the ways that neurocognitive status may influence and, in turn, be affected by risk and protective factors as well as contextual variables and the possible synergy between negative cognitive biases/distortions and neurocognitive impairment.⁵⁰

Further evidence is also needed to assess the role that cognitive and neuropsychological impairment may play in disrupting an individual’s ability to adaptively cope with adverse life circumstances and, thus, heighten the risk for suicidal behavior.

Presumably, patients who have cognitive/neuropsychological impairment and a combination of neurodevelopmental, neuropsychiatric, and neurologic factors would be at greater risk for suicidal behavior than patients with fewer of these influences when controlling for the relative severity of these factors in a given case. Research would be helpful to address the possible additive or synergistic impact on the susceptibility to various types of suicidal behavior.

Impaired neurocognition (especially compromised executive functioning) may impede the ability to effectively engage in serious suicidal behavior. Evidence-based data are needed to support this idea.⁴⁸ It would also be desirable to clarify the role of higher level cognitive/neuropsychological functioning as a potential risk vs protective factor. Well-developed executive skills can be a double-edged sword: On the one hand, good executive functioning could be an asset for safety planning and alliance building; conversely, good executive functioning may facilitate the planning and execution of high lethality suicidal behavior.

The potential responsiveness of cognitive/neuropsychological impairments to psychopharmacological interventions as well as nonpsychopharmacologic approaches like cognitive rehabilitation also merits further study.⁵⁸ This could shed light on trait versus state conceptualizations of cognitive/neuropsychological impairment in relation to suicidal behavior, as well as the role such interventions might play in harm reduction.⁵⁹

In addition, it would be helpful to have research that incorporates a wider demographic. This is especially true for adolescents and older adults because of well-documented risk for suicidal self-harm.⁴⁹

To properly address these issues, more data are needed to ascertain the ability of specific tests and/or score profiles to differentiate patients with high vs low risk for serious suicidal behavior. This would include the possible identification of test profiles that may heighten vs attenuate risk within varying time frames: imminent (days), near term (weeks), and long term (months).

Future research also could identify patterns of cognitive/neuropsychological functioning related to the spectrum of suicidal self-harm behaviors. Such knowledge could facilitate the prediction of potentially serious outcomes, as well as differential response to harm reduction/safety interventions. This continuum encompasses morbid rumination, passive suicidal thinking, active suicidal thinking with and without plan and/or intent, impulsive versus planned suicide attempts, high vs low lethality attempts, and completed suicide.

If tests or sets of measures have consistently good sensitivity/specificity, they may also help to further an understanding of the neuroanatomical substrates of suicidal behavior.⁴⁹

To advance these research aims, the use of a standardized battery of cognitive/neuropsychological tests, along with good psychometric properties that tap a broad range of neurocognitive domains, would be highly desirable. This data would allow for more meaningful comparisons and conclusions across studies.⁴³ Preferably, assessments should include the domain of social cognition which, to date, does not figure prominently in research on neurocognition and suicidal behavior. Screening tests like the Screen for Cognitive Impairment in Psychiatry might serve as the basis for the development of such a research battery.⁵⁷

Imminent and short-term suicidal behavior, especially serious suicide attempts and death from suicide, continue to be unpredictable.

Concluding Thoughts

Imminent and short-term suicidal behavior, especially serious suicide attempts and death from suicide, continue to be unpredictable.^1,32

However, a good working knowledge of a patient’s neurocognitive status might enhance predictive validity and improve symptom management and safety planning. This information could be obtained from psychometric testing coupled with clinically relevant information gleaned from further research on the relationships between neurocognitive test performance and suicidal behavior. Such improvements could lead to improved quality of life for patients who are suicidal, and to lives being saved.

Dr Pollak is a clinical psychologist and neuropsychologist, Emergency Services, Seacoast Mental Health Center, Portsmouth, New Hampshire; and an allied health professional, Department of Medical Services, Section of Psychiatry, Exeter Hospital, Exeter, New Hampshire. He reports no conflicts of interest regarding the subject matter of this article.

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