Substance Abuse Disorders

Evidence and Experience

Hamid Ghodse, Helen Herrman, Mario Maj, Norman Sartorius, Hamid Ghodse, Helen Herrman, Mario Maj, Norman Sartorius

• Publisher: Wiley
• Year: 2011
• Print ISBN: 9780470745106
• eBook ISBN: 9780470975947
• Edition: 1
• Topic: Medicine
• Subtopic: Psychiatry & Mental Health

Substance abuse disorders are among the most prevalent psychiatric disorders and are frequently comorbid with other psychiatric and health conditions and accompanied by social problems; however, they remain under-recognized and under-treated. Many physicians and mental health practitioners receive little-to-no training in the identification and treatment of these disorders.  Approaches to their prevention include some of the major success stories in modern public health as well as some of the deepest controversies in public life. This new title in the WPA series Evidence and Experience in Psychiatry informs psychiatrists and a wide range of professional groups from health and social services about these disorders and their treatment and control. 

'Highly Commended' in the Psychiatry section of the 2012 BMA Book Awards

Section 1

Drugs

Chapter 1

Epidemiology of Drug Abuse: A Global Overview

Maria-Elena Medina-Mora, PhD, Tania Real, M.S. and Rebeca Robles, PhD

Division of Epidemiology and Psychosocial Research, National Institute of Psychiatry, Ramón de la Fuente Muñiz, México, Mexico

1.1 INTRODUCTION

Public Health is interested in the health condition of the population and in the relation between the health status of groups and the environment. Epidemiology, through the differentiation of healthy individuals from those in poor health, and by the study of biological and social, individual and collective factors related to health and disease, estimates the extension and magnitude of a problem, subgroups of the population affected, trends over time, its determinants and consequences, the proportion of persons exposed to preventive interventions and the treatment demand covered. Its challenge is to describe the problem in a way that provides the evidence required to orientate policy.

Providing a comprehensive view of the drug problem across different cultures poses some difficulties, mainly derived from the availability of accurate information. On the one hand, illicit activities are difficult to evaluate, willingness to report might be affected by social tolerance toward drug use; persons conducting surveys in countries where drug use is defined as a felony and the police are active, might find more difficulties in obtaining an adequate rate of persons accepting to answer a questionnaire and an accurate self-report of use. Also, studies conducted in different countries might reflect differences in methods pursued, populations covered and conceptual definitions of behaviours and consequences, more than variations in rates of use. In spite of these limitations, data available show interesting global trends that can serve as an arena for the discussion of drug policies.

This chapter provides a view of the extension of the problem per type of substance and in different regions of the world; it is introduced by a discussion related to the different approaches epidemiology can follow, it provides evidence on the need to study dimensions of use and problems as separate interacting indicators and of considering the circular nature of the drug problem with epidemic rises, periods when drug use is stable or is reduced, followed by a new rise, that calls attention to the need to consider replicating studies with a periodicity that allows the description of trends.

Data included in the chapter are drawn from a literature review, from the reports of member countries to the United Nations, from the annual reports of the International Narcotics Control Board, the UNESCO and from statistics and other studies coordinated by the World Health Organization. Regional organizations such as the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), the Inter-American Drug Abuse Control Commission CICAD, were also visited. This information is completed with data coming from epidemiological studies, household and student surveys, and surveillance systems, when available.

1.1.1 The Scope of Epidemiology

Epidemiology seeks to answer questions such as is there a drug problem? If so, what type of problem? What is its impact at the national and local levels? And depending on the type of problem, what are the more appropriate policies?. To answer these questions it uses surveys and other methodological strategies to assess the prevalence of use and abuse, problems and trends based on conceptual models that provide specific definitions of the problem, the accepted indicators to measure it and the policy to follow. The following section describes the main sources of information available:

A. Estimates of production and drug seizure. The availability of drugs in local markets can be derived from studies that assess the cultivation and production of drugs and from seizures that provides information about price and purity of individual drugs and about the type of substances that are available in certain locations, provided it is possible to differentiate quantities aimed for exportation and quantities aimed for local markets, especially in transit countries. In analysing this data caution must be taken as changes in price and purity of illegal substances on the streets do not necessarily indicate changes in prevalence; variations in effectiveness of enforcement and in reporting efforts can also shape this information [1].

B. Estimating prevalence. Counting the number of individuals that have used drugs is not enough to determine the scope of the problem in a given society. The impact of the drug problem on public health and thus the type of problem to be faced is modulated by:

I. The patterns of drug use, that include the type of substances used, the routes of administration, the frequency and quantity of intake, the subgroup of the population using them (i.e. pregnant females, adolescents, etc.) or the circumstances of use (i.e. driving under the influence of drugs).

II. The likelihood of dependence and of other drug-related problems influenced by variations in the vulnerability of individuals genetic predispositions (i.e. heritability estimates a range between 40 and 60% [2], factors in the development that increase the likelihood of transiting from experimentation to heavy use and dependence (i.e. childhood adversities including exposure to violence), in variations in the proximal environment (i.e. drug availability, drug use amongst siblings and peers, etc.).

III. Sociocultural factors that include tolerance to use of drugs, demographic such as increase in the proportion of young persons with no equivalence in the availability of school and job opportunities, or social transitions such as migration. These factors modulate the likelihood of experimenting with drugs and advancing towards dependence as well as its impact in different societies.

IV. Availability of resources to face the problem (i.e. universal or limited access to treatment and other social services) and health and social policies that modulates the availability of resources to cope with the problem. Lower rates of use might result in a greater burden when they occur in contexts of poverty, social inequity or high degree of delinquency, or when there are no resources to identify cases and offer treatment. Formal responses to the problem will affect the availability of drugs on the streets and the number of persons imprisoned for drug use or possession. Special features of the illegal production, diversion from legal sources and traffic of drugs and organized crime will also affect the problem, influencing the rate of violence and drug availability.

C. Mortality and morbidity. Mortality studies focus on the most serious forms of drug abuse, causes being numerous from direct causes such as overdose, to indirect accidents or murder; they can relate to the route of administrating drugs or specific lifestyles such as HIV, hepatitis B or C. Mortality information can be driven from national causes of death statistics, examinations from the medical examiner, police or hospital records, amongst other sources [1]. The accuracy of information varies from country to country. According to Single et al. [3] illicit drugs have been implicated as a sufficient or contributory factor in at least 90 causes of death and disease. For each of these causes it is possible to estimate the excess mortality of persons with an addiction as compared to the general population controlled by age and sex [4], it is also possible to estimate aetiologic fractions or attributable proportions and estimate the numbers of deaths and admissions to hospital that can be causally attributed to illicit drugs.

D. These indicators can be resumed in a concept known as burden of disease, that includes premature mortality attributable to the disease and days lived without health. Substance-attributable burden is usually estimated by combining relative risk data with exposure prevalence data and disease-related mortality and morbidity information, from national databases [5].

The extent of drug use and the social perception of the extent of the problem does not always show the same trend, for instance a stabilization in drug use and even a reduction of new cases after a period of rapid increase can be accompanied by an increase in problems and of the demand for treatment as a result of chronic use by a proportion of those that started experimenting some time back. This trend can be accompanied by more visibility if an increase in murders occurs as a result of modifications in the drug cartels organization and their fight for markets, or if public policies change, or if the mass media focuses more closely on an old problem, modifying the social perception. The challenge of epidemiology is to assess the problem from a scientific perspective and to deliver knowledge in a way that is understood by the population, especially those that are in charge of public policies.

In summary, knowledge about the number of persons that use, abuse or become dependent and the trends over time is an important base for policy, but might not be enough to understand the impact of the problem in a given society. Approaches that evaluate the problem on two axes, substance use on the one hand and problems on the other, and that analyse their interrelation in the sociocultural context can provide a more accurate view of the problem by integrating in the analysis of prevalence, drug supply, individual and contextual variations, social perceptions of the problem and policies [6].

1.1.2 Conceptual Framework

Paradigms underlying epidemiological studies are also central because they define the basic suppositions upon which the problem is constructed, the aetiological explanations that are provided, indicators that are accepted as valid for its study and as such it is closely related to the way policies are conceived and actions are taken to counteract the problem [7].

The paradigm of infectious diseases conceives disease as a result of the interaction of a host with different degrees of susceptibility, exposed to an agent, in defined modes of transmission and environments; this model has been extended to study behavioural disorders such as drug abuse. The paradigm is mechanical biological and determinist in nature and follows a logical lineal causal mode. Public health interventions derived from this explanation seeks to block the casual link by eliminating the agent and by protecting the host, reducing the level of exposure to the agent and modifying the environmental conditions that facilitate exposure. The epidemiological tools are surveys to determine the proportion of the population exposed and that using drugs, the notification systems and the follow up of individuals to determine the routes of contact.

In accordance with the disease model, the more salient policy during the last century was the reduction of supply. It was assumed that the expansion of the problem could be prevented by reducing the opportunities of exposure that in turn depended on drug availability.

This notion of the individual as a passive host affected by an agent if exposed gave way to a more complex formulation that conceived an individual actively seeking for the agent. The resulting psychosocial paradigm considers the multifactor nature of the phenomenon; replaces the concept of a unique casual agent for the exposure to a wide variety of risk or protecting factors that affect the likelihood of an individual to experiment with drugs or to develop dependence.

Actions derived from this paradigm place less emphasis on the control of the agent, instead it aims at the reduction of risk factors and the enhancement of factors that make the individual less vulnerable or more resistant to the risks present in his environment; promotes healthy lifestyles and health protection through education. Interventions were then aimed at increasing the resilience of individuals to drugs. This model shares the linear causal model of the infectious diseases model and fails to explain variations derived from more distant contextual factors such as the role of affluence or extreme poverty and unemployment.

The tradition in psychiatric epidemiology, by definition more interested in substance-abuse disorders than in their use, includes symptoms as indicators. The use of this approach has made important contributions in the determination of treatment needs and the proportion covered, but provides information on only one of the elements of the drug phenomenon, this is dependence.

A phenomenological model considers that behaviour is mediated by cognitive processes through which the individuals construct the meaning of the world in which they live. Alternative models consider that public policy in itself plays a causal role in the shaping of the problem and in the social response.

The increase in problems in different regions, globalization and perhaps also the claim of drug-producing developing nations that the demand of drugs in the developed world was eliciting supply, turned to the recognition of the need of a more balanced approach in the efforts and budgets aimed at reducing both supply and demand. This conception has gone even further, by considering that only an integrated approach that combines components of supply and demand could make a difference.

A model based on drug marke...

Table of contents

• Cover
• Series
• Title Page
• Copyright
• List of Contributors
• Preface
• Section 1: Drugs
• Section 2: Alcohol
• Section 3: Tobacco
• Index