Further confounding the use of assessment tools is their misuse. At times, researchers have used one or two items from an assessment scale, when the tools have only been validated in their full form. Studies frequently use just a single item from the Hamilton Depression Scale, a practice which results in a decreased sensitivity of the assessment tool. Complete, standardized suicide assessment measurements are most appropriate in clinical trials.
Instruments may not have the same predictive utility when used in populations other than those in which they were developed (Meehl and Rosen, 1955). The base rate of risk factors may vary significantly across different populations, so that the same level of a risk factor may have significant predictive utility in some groups, but not others. In addition to base rate differences, risk factors may vary in meaning, salience, and/or presence across groups. The prevalence of risk factors for suicidal behaviors differs in different samples or population groups, just as the base rates of suicidal ideation and suicide attempts differ. Moreover, some instruments may be more appropriate than others for certain age groups, and some instruments may be more “culturally sensitive” than others. For these and other reasons, an instrument that has been demonstrated to be of use in one population may not be as useful with other groups.
Instruments developed with school-based or community samples may not have the same predictive utility in “high-risk” or clinically ascertained samples, and vice versa. Risk factors in a community may not be useful as a predictor of suicidal behavior in higher risk populations. First-time suicide attempters may differ from those who attempt more than once, and predicting first and later attempts may involve different risk factors. Goldston’s team (2001) found that hopelessness was a strong predictor of future suicide attempts following hospitalization among adolescents who previously had made at least a single suicide attempt, but hopelessness was not a significant predictor in those without a history of suicide attempt(s).
The relationship between vulnerability factors assessed with risk instruments (distal risk factors) and precipitating stresses (proximal risk factors) needs to be better understood. Using instruments focused on identifying groups based on various risk factors may tell us who is at risk,