Negative early life experiences as risk factors for suicidal behavior in bipolar disorders.

Most suicidal behavior (thoughts, attempts and completion) occurs in the context of a psychiatric illness, of which bipolar disorder (BD) is associated with the highest risk for suicide.1 Several studies and meta-analyses have shown that 34 to 50% of individuals with bipolar disorder have a lifetime history of suicide attempts. Epidemiological studies show a 10-15% mortality rate by suicide in BD. Finally, the standardized mortality ratio for suicide deaths has been reported to be 10- to 30-fold in BD compared to the general population. This leads to suicide being a main factor in the 10-13 years of premature mortality in BD. Given the magnitude of the problem, it is essential to strengthen the study of risk factors associated with suicidal behavior in BD. Moreover, it is important to investigate which factors make suicide more prevalent in BD than other psychiatric disorders and whether risk factors associated with suicidal behavior in the general population have a different role and impact in BD.

Suicidal behavior is influenced by several factors. Understanding the diathesis together with the precipitating factors that trigger the behavior is fundamental. Some of the most relevant predisposing and precipitating individual risk factors for suicidal behavior in BD include gender (females have higher rates of attempts and males have higher rates of completion), prior suicide attempt, family history of suicide, rapid cycling, bipolar type I, early onset, aggression and impulsivity, stressful life events, drug and alcohol abuse/misuse disorders, comorbid anxiety disorders, Axis II comorbidities, and child abuse and maltreatment.2

Distal life stressors such as childhood adversity, especially child abuse, have been increasingly associated with suicidal behavior in BD. Child maltreatment (CM) is highly prevalent in BD and is associated with a worse course and prognosis.3 More specifically, early physical and sexual abuse have been associated with an elevated risk of suicide. Agnew-Blas & Danese have published a meta-analysis that associated CM in bipolar disorder with several unfavorable clinical features and outcomes, including a higher risk of suicide attempts compared with BD patients who were not abused.4 Genetics and early negative life events are vulnerability factors and may contribute to the development of specific neurobiological abnormalities, including stress response system dysfunction, neuroinflammation, impaired neural plasticity, serotonergic and glutamatergic dysfunction, etc.5 These effects may ultimately lead to an abnormal neural substrate that leaves the individual more vulnerable to stressful life events later on in life that could lead to suicidal behavior.

There is increasing evidence that different types of early life events may contribute distinctively to suicide risk and behavior in BD. The impact of childhood sexual and physical abuse, emotional abuse and emotional and physical neglect on suicidal behavior may differ. However, the impact of CM on the course of and suicidality in BD has been previously evaluated with different instruments, resulting in high heterogeneity in assessments and outcome measures. In this issue of the Brazilian Journal of Psychiatry, Duarte et al. try to address some of these issues by performing a systematic review and meta-analysis of published studies.6 In this review, the authors aimed to decrease heterogeneity by selecting studies that used a single instrument to assess CM, the Childhood Trauma Questionnaire (CTQ). The CTQ is the most widely used quantitative measure of CM in the literature. It generates a general total score but also assesses five different types of CM (childhood sexual and physical abuse, emotional abuse and emotional and physical neglect). The authors’ objective was to evaluate a more homogeneously assessed sample compared to previous meta-analyses, such as that of Agnew-Blas and Danese. In the meta-analysis of 6 published studies, they found that bipolar suicide attempters had a higher frequency of CM and had higher total CTQ scores. Moreover, some types of CM had larger effect sizes (sexual and emotional abuse) than others (emotional neglect and physical abuse and neglect). This new meta-analysis confirms the findings of previous studies and adds important new data. In addition, the medium and small effect sizes they found confirm that CM is one of several factors that play a role in this extremely complex and multifactorial condition. The recognition of negative early life experiences as risk factors for suicidal behavior in BD has 2 distinct implications: first, clinicians should include evaluation of CM in psychiatric assessments of BD; second, CM could be targeted in public policies aiming at suicide prevention. Finally, pharmacological and psychosocial treatments are effective for acute and long-term BD treatment, but we have seen little progress in suicide mortality in recent decades. A better understanding of the process involved in suicide vulnerability and risk in BD is fundamental for improving preventive measures aimed at decreasing the burden and mortality of the illness, and this meta-analysis contributes to this objective.

Disclosure

BL reports no conflicts of interest. MAO receives royalties from the Research Foundation for Mental Hygiene for the commercial use of the Columbia Suicide Severity Rating Scale and owns equity in Mantra, Inc.; her family owns stock in Bristol Myers Squibb.