20 - Putting epidemiology and public health in needs assessment: drug dependence and beyond

Summary

Summary

This chapter makes a case for intervention at early stages of drug involvement, well before a drug user meets diagnostic criteria for drug dependence. The case for early intervention rests upon a foundation of epidemiological evidence about the person-to-person spread of drug taking and the quite rapid transition into drug taking and the drug dependence process, once an opportunity to try a drug has occurred. In addition, co-occurring psychiatric and behavioral disturbances among many drug-dependent individuals complicate clinical decisions about diagnosis and therapeutics. This complexity warrants the earlier rather than later attention of skilled clinicians.

Introduction

Over the years, our agenda for international meetings on psychiatric epidemiology has ranged from the question ‘what is a case?’ to ‘how many need treatment?’ These questions appeal to basic concepts from the theory of sets. Consider one set, consisting of all inhabitants of a mental health catchment area or a church/civil parish, such as were surveyed for mental disorders in Norway more than 150 years ago (Holst, translated by Massey, 1852). The members of this set can be sorted into two mutually exclusive and exhaustive subsets: set members who qualify as active ‘cases’ and set members who qualify as ‘non cases’. An alternative course of action is to sort the original set members into two subsets, one consisting of all people who need treatment and the other consisting of all those who do not.

Some observers will tell us that these two courses of action amount to one and the same thing. That is, cases need treatment services, whereas non cases do not. This represents a widely accepted conceptual model for needs assessment planning in the field of drug dependence.