Psychiatric problems may be the cause or the effect of many toxicologic presentations. Suicide attempts and aggressive behaviors are commonly associated with toxicity and can be uniquely difficult to assess and manage. Patient behaviors are often viewed as either totally intentional and deliberate or totally "out of control" and irrational. The truth is usually more complex, with some aspects occurring within the awareness and control of the patient and other aspects either unknown or overwhelming to the patient. This chapter addresses suicide and violence to enable the physician to adopt the appropriate role of both diagnostician and medical decision maker.
Although suicide may be attempted or accomplished in a variety of settings and by a variety of means it is most typically associated with psychiatric disorders and/or substance abuse, especially ethanol, and is typically accomplished with psychoactive xenobiotics alone or in combination.37,39
Suicide is a leading cause of death and injury in the United States and throughout the world. Suicide was the 11th leading cause of death in 2005, with the 32,637 known cases representing 1.3% of the total deaths in the United States that year. The age-adjusted death rate in 2005 was 10.9 deaths by suicide for every 100,000 persons, or 0.0109%.13 Suicidal ideation and attempts are far more frequent than actual suicide. Recent studies published since 1999 have demonstrated that among individuals age 18 and above, lifetime prevalence rates for suicidal ideation are 5.6%–14.3%. The lifetime prevalence rate for suicidal plans is 3.9% and the lifetime prevalence rates for suicide attempts are 1.9%–8.7%.13,14
Although the prevalence of suicide and suicidal behaviors shows significant overlap, one notable area of difference is the consistent pattern of higher rates of suicide attempts among women and of completed suicides among men.13,14 For adolescents aged 12–17, lifetime prevalence rates for suicidal ideation are 19.8%–24.0%. Lifetime prevalence rates for suicide attempts are 3.1%–8.8%. Twelve-month prevalence rates for suicidal ideation are 15.0%–29.0%. Twelve-month prevalence rates for suicide attempts are 7.3%–10.6%. Twelve-month prevalence rates for suicide plans are 12.6%–19.0%. There are no lifetime data on suicide plans.14,15,46
Given that the act of suicide is a statistically rare event in the overall population, it is virtually impossible to predict who will actually commit suicide. It is therefore critical to identify risk factors that increase the likelihood that any individual might attempt suicide, and to identify risk factors that are modifiable. The identification of modifiable risk factors provides opportunities for interventions that may decrease suicide risk. Additionally, there are protective factors that mitigate the risk for suicide, and it is important to assess for the presence or absence of these factors in determining the overall risk for suicide in a patient.
The terms and definitions of suicide and suicidal behaviors used in this chapter have been outlined in several reports on the subject.24,32,...