Roberta G. Ferrence

Sex and Age Patterns in Self-Injury*

Age and sex differences in rates of self-injury are prominent and relatively unexplained. A prospective study of self-injury patients resident in London, Canada was carried out between 1969 and 1971. It wasfound that rates of self-injury are higherforfemales andforyoung persons, compared with suicide rates which are higherfor males and for older persons. Other factors related to rates of self-injury are also examined, but the basic age and sex patterns persist when these variables are controlled. These findings indicate that self-injury among the young, especially young females, has considerably less lethal risk than among older persons, especially males. For this reason, self-injury may have rather different motivation and be surrounded by different circumstances that serve to differentiate the classes of events. A preliminary theoretical model is proposed which relates self-injury to suicide and other forms of reaction to stress. The study of suicide and attempted sui- cide has long exerted a strange fascina- tion for scholars, which has resulted in more study than the subject matter has seemed tojustify either as a cause of death or as a problem of social importance. Only in recent years has the extent of self-injury behavior in the population begun to be uncovered. As a result, students of this subject are becoming aware that self- injury is much more common than they had thought, hence a greater cause for concern. For example, a Canadian pro- spective study of self-injury behavior in London, Ontario, recently reported a rate of 730 cases of self-injury per 100,000 population, a rate several times highei than is usually associated with this * This project was supported by grants from the following sources: The Ontario Mental Health Foundation (#241); the Public Health Research Grants Division of the Department of National Health and Welfare (#605-7-585); and the Canada Council (#573-0294-51). phenomenon. Moreover, evidence sug- gests that actual rates of self-injury in the population may be as high as 1400 cases per 100,000 population per annum (Whitehead, Johnson and Ferrence, 1973). According to these reports, the high rate in London probably does not reflect a high propensity for self-injury in the local population. Rather, it indicates a more complete description of existing patterns of the incidence of self-injury (Ferrence and Johnson, 1974). If the unknown but reputedly much higher rates of threatened self-injury are added to these known rates, we begin to become aware of the importance of self-injury as a technique in human relations. Of the many areas of analysis of suicide and self-injury that are reported in the literature, the interrelationships of sex and age comprise one of the most intri- guing sub-sets for potential further study. The purpose of this paper is to report and

Studies of Driver Impairment and Alcohol-Related Collisions

The study of driving impairment and alcohol-related collisions is complicated by the fact that relevant data are derived from a variety of sources and are based on different groups of drivers. In order to discover changes in the magnitude of driving impairment and collisions and to assess the effects of countermeasures of various types, it is essential to understand the nature of these differences and to establish the validity and reliability of the findings. The purpose of this chapter is to assess systematically the different sources of information that are available on this topic, indicate the advantages and disadvantages of each, specify the uses to which they can best be put, and identify the major gaps in our knowledge.