An Unmatched Case‐Control Study of Nearly Lethal Suicide Attempts in Houston,Texas: Research Methods and Measurements

T his article details the research methods and measurements used in conducting a population‐based, case‐control study of nearly lethal suicide attempts among persons aged 13–34 years, residing in Houston, Texas. From November 1992 to July 1995, we interviewed 153 case subjects presenting at one of three participating hospital emergency departments and used random digit dialing to identify 513 control subjects residing in the same catchment area in which cases were enlisted. Unlike most research in this area, this study was designed to extend our understanding of suicidal behavior and prevention activities beyond identification and treatment of depression and other mental illnesses. We discuss the overall strengths and weaknesses of our study design and conclude that this methodology is well suited for studying rare outcomes such as nearly lethal suicide.     

Help‐Seeking Behavior Prior to Nearly Lethal Suicide Attempts

T he association between help‐seeking and nearly lethal suicide attempts was evaluated using data from a population‐based, case‐control study of 153 13‐ to 34‐year‐old suicide attempt case‐patients treated at emergency departments in Houston, Texas, and a random sample of 513 control‐subjects. Measures of help‐seeking included whether the participant sought help for health/emotional problems in the past month, type of consultant contacted, and whether suicide was discussed during the interaction. Overall, friends/family were consulted most frequently (48%). After controlling for potential confounders, case‐patients were less likely than control‐subjects to seek help from any consultant (OR = 0.5, 95% CI = 0.3–0.8) or a professional (e.g., physician, counselor) consultant (OR = 0.5, 95% CI = 0.29–0.8). Among those who sought help, case‐patients were more likely than to discuss suicide (OR = 2.6, 95% CI = 1.2–5.4), particularly with professionals (OR = 11.8, 95% CI = 3.2–43.2). Our findings suggest that efforts to better understand the role of help‐seeking in suicide prevention, including help sought from family and friends, deserves further attention.     

Alcohol Consumption and Nearly Lethal Suicide Attempts

W e conducted a case‐control study of the association between nearly lethal suicide attempts and facets of alcohol consumption; namely, drinking frequency, drinking quantity, binge drinking, alcoholism, drinking within 3 hours of suicide attempt, and age began drinking. Subjects were 13–34 years of age. In bivariable analyses, all measures were associated with nearly lethal suicide attempts. Odds ratios ranged from 2.4 for alcoholism to 7.0 for drinking within 3 hours of attempt. All exposure variables except age began drinking exhibited a J‐shaped relationship between alcohol exposure and nearly lethal suicide attempt. After controlling for potential confounders and other measures of alcohol exposure, drinking within 3 hours of attempt remained most strongly (odds ratios > 6) associated. Alcoholism remained significantly associated in most models, but at lower strength.     

Medical Conditions and Nearly Lethal Suicide Attempts

P hysical illness has been studied as a risk factor for suicidal behavior, but little is known about this relationship among younger persons. We conducted a population‐based, case‐control study in Houston, Texas, from November 1992 through September 1995. The final sample consisted of 153 case‐ and 513 control‐subjects aged 13 to 34 years. Case patients were identified at hospital emergency departments and met criteria for a nearly lethal suicide attempt. Control subjects were recruited via a random‐digit‐dial telephone survey. Case patients were more likely than controls to report having any serious medical conditions (crude OR = 3.23; 95% CI = 2.12–4.91). After controlling for age, race/ethnicity, alcoholism, depression, and hopelessness, the adjusted odds ratio for men was 4.76 (95% CI = 1.87–12.17), whereas the adjusted odds ratio for women was 1.60 (95% CI‐0.62–4.17), suggesting that young men with medical conditions are at increased risk for nearly lethal suicide attempts. Increased efforts to identify and appropriately refer these patients are needed.     

Identification of Nearly Fatal Suicide Attempts: Self-Inflicted Injury Severity Form

The Self-inflicted Injury Severity Form (SIISF) was developed as an epidemiological research tool for identifying individuals in hospital emergency departments who have life-threatening self-inflicted injuries. Data were collected from 715 patients with self-inflicted injuries in two large hospitals. In 295 of these cases, a second set of data was independently collected for assessment of interrater reliability. Validity was assessed by comparing the SIISF results with simultaneously collected Risk—Rescue Ratings. Assessment of interrater reliability found that only 2.4% of physicians disagreed on the suicide method used. The kappa statistic for method used was .94, indicating excellent agreement. The SIISF was found to distinguish between severe and less severe injuries. Thus, it appears to provide a simple method to distinguish patients who have life-threatening self-inflicted injuries.     

The Influence of Geographic Mobility on Nearly Lethal Suicide Attempts

T eenagers and young adults are very mobile and mobility has been identified as a potential risk factor for suicidal behavior. We conducted a population‐based, case‐control study of nearly lethal suicide attempts with 153 cases and 513 controls. Study participants were asked about changing residence over the past 12 months. Results indicate that moving in the past 12 months is positively associated with a nearly lethal suicide attempt (adjusted odds ratio of 2.1, with 95% confidence interval of 1.4–3.3), as are specific characteristics of the move (e.g., frequency, recency, distance, and difficulty staying in touch). These findings confirm and extend prior ecologic research by demonstrating a relationship, at the individual level, between the geographic mobility of adolescents and young adults and nearly lethal suicide attempts.     

Characteristics of Impulsive Suicide Attempts and Attempters

S uicide attempts often are impulsive, yet little is known about the characteristics of impulsive suicide. We examined impulsive suicide attempts within a population‐based, case‐control study of nearly lethal suicide attempts among people 13–34 years of age. Attempts were considered impulsive if the respondent reported spending less than 5 minutes between the decision to attempt suicide and the actual attempt. Among the 153 case‐subjects, 24% attempted impulsively. Impulsive attempts were more likely among those who had been in a physical fight and less likely among those who were depressed. Relative to control subjects, male sex, fighting, and hopelessness distinguished impulsive cases but depression did not. Our findings suggest that inadequate control of aggressive impulses might be a greater indicator of risk for impulsive suicide attempts than depression.