National suicide prevention programmes that have been successful in reducing rates or keeping them low have been intentional, with collective alignment of local, regional and national priorities. Prevention efforts must begin well before individuals become suicidal, complementing readily available clinical services that address the needs of acutely distressed persons. These efforts, which focus on the antecedent risks and vulnerabilities of key populations, have the potential to diminish premature mortality from multiple causes, even as reducing suicide is the outcome of primary interest. In this commentary, I consider four key challenges that must be confronted in order to develop effective, broadly reaching systemic strategies that, at once, can be adapted locally while being implemented nationally – challenges that are framed in a social–ecological context. They involve defining the scope of the problem, meeting essential data needs, developing and modelling measurable implementation strategies and building prevention efforts based on shared culture and values.

Ternary variations of the II-VI zincblende semiconductors have received little attention for thermoelectric applications. Here we present the first systematic doping study on Cu3SbSe4, a zincblende-like ternary semiconductor with a unit cell four times larger than the parent II-VI compounds. The large unit cell of Cu3SbSe4 results in a low room temperature thermal conductivity (~3.0 W/m*K) and its large hole effective mass produces a Seebeck coefficient approaching 500 μV/K in the undoped compound. Our results show that Ge is an effective p-type dopant in Cu3SbSe4, and the power factor reaches nearly 16 μW/cm*K2 at 630K when 3% Ge is added, rivaling that of state-of-the-art thermoelectric materials at this temperature.

In traditional medical use, a categorical diagnosis conveys essential (although stereotypic) information about the signs and symptoms of a disease, its treatment, and its prognosis. Its utility derives from its generalizability. However, many of the shortcomings of categorical classification also reflect these same qualities. Diagnoses too often fail to capture important qualities of a disorder or do not sufficiently characterize a patient's particular symptoms. Recent editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM), which have emphasized highly specific entry criteria to establish psychiatric conditions in a more homogeneous fashion, have sometimes resulted in enhanced reliability at the cost of diminished validity. The variability of psychiatric disorders often defies attempts to create strictly defined clusters amenable to syndrome classifications.

Age of onset of depressive episodes may serve as a useful marker of pathogenetic heterogeneity in late-life depression. Medical illness may play an important role in the pathogenesis of depression in the elderly, but its relationship to age of onset has not been carefully examined. We prospectively studied 110 older inpatients with DSM-III-R major depression. Using multiple regression techniques, we found that medical illness was not independently associated with age of onset. Independent predictors of older age of onset were age, male sex, absence of substance abuse history, and absence of melancholia. Our discussion reconsiders the usefulness of age of onset as a primary research variable for elucidating heterogeneity of late-life depression.

The authors report preliminary data from a psychological autopsy study of completed suicide in late life. Sixteen of 18 victims had diagnosable psychopathology, most commonly major depression of late onset. Symptoms manifest prior to death are described and directions for future investigation discussed. The psychological autopsy is shown to be a viable method for studying suicide in the elderly.

There is an accumulating body of research suggesting that suicidal behavior may be associated with abnormalities of the central serotonin system. Other monoaminergic, peptidergic, and neuroendocrine systems have been implicated as well. A review of studies that examine neurobiological variables in postmortem tissue of suicide victims and controls reveals that investigators in most instances have viewed age as a confound to be controlled rather than considering it as a variable of interest. However, the close associations between aging and increased suicide rates, and the knowledge that the functional integrity of many of these same systems changes with normal and abnormal aging processes, raise the possibility that biological aging contributes to suicide risk, and that the underlying neurobiology of suicide in the elderly differs from that of younger people. The few available studies that did examine the association of age with neurobiological measures indicate directions for future research into the role that aging may play in determining the biological bases of suicide risk.

Establishing a medical diagnosis serves two utilitarian purposes: providing information necessary to initiate treatment and communicating information regarding prognosis. A nosology or diagnostic nomenclature (i.e., a classification of diagnoses) provides further utility by establishing a foundation for clinical research. In his book, Wulff outlined four types of diagnoses: (1) symptomatic or pseudoanatomic diagnoses (e.g., chronic headache, persistent diarrhea, or irritable bowel); (2) syndromes; (3) anatomic diagnoses; and (4) causal diagnoses. By definition, syndromes have no means of being validated by measures external to the constructs themselves. Often, specific syndromes reflect diverse origins, and conversely, specific etiologies may cause multiple syndromes (e.g., syphilis, human immunodeficiency virus, and diabetes).

Suicide is an action that calls for explanation. Many who kill themselves leave written words behind, attempting to explain, but many others do not. For those outside the experience, there remains a need to understand. Self-inflicted death may make sense occasionally, however painful it may be to those left behind. Most often, it is called a tragedy, death before one's time.

We compared the verbal learning and memory performance of 57 inpatients with unipolar major depression and 30 nondepressed control participants using the California Verbal Learning Test. The effect of age within this elderly sample was also examined, controlling for sex, educational attainment, and estimated level of intelligence. Except for verbal retention, the depressives had deficits in most aspects of performance, including cued and uncued recall and delayed recognition memory. As well, there were interactions between depression effects and age effects on some measures such that depressives' performance declined more rapidly with age than did the performance of controls. The results are discussed in the context of recent contradictory reports about the integrity of learning and memory functions in late-life depression. We conclude that there is consistent evidence, from this and other studies, that elderly depressed inpatients have significant deficits in a range of explicit verbal learning functions. (JINS, 1998, 4, 115–126.)