Relationships Between Mental Health and Drug Abuse Epidemiology


Before discussing the topic assigned to me – the relationship between mental health and drug abuse epidemiology  ̶ I should like to comment on the essential role of epidemiologic research in our efforts to prevent and control disease, disability and major social problems. These comments were stimulated by the remarks of the prior speaker, who seemed to have doubts about the importance of such research.

Epidemiological profiles of diseases and disabling conditions for the U.S. as a whole  ̶ and their variations among regions, States, counties, cities and other geographic subdivisions serve many important purposes. Data on the size of these problems, their costs to the Nation and their social impact are essential to the process of getting the support of Congress, State legislatures and local governments to establish programs to prevent and control these problems and provide the funds and manpower needed to implement them. Planners need such data to develop strategies for attacking these problems. Evaluators need baseline and other types of data to measure the effectiveness of efforts to combat these problems. These include incidence, duration and severity of disability, mortality rates and related indices. The uses to which such epidemiologic data are put have been admirably summarized by Morris.

  1. 1. To assess changes over time in incidence and prevalence of diseases, the disability they cause and their mortality.
  2. 2. To diagnose the health of the community and the conditions of the people, to measure the dimensions and distribution of the problems of disease and disability, to define health problems for community action and their relative importance and priority for action, and to identify vulnerable groups needing special protection.
  3. 3. To study and assess the health services with a view to their improvement.
  4. 4. To estimate individual risks, on the average, of acquiring various diseases and conditions.
  5. 5. To identify syndromes.
  6. 6. To complete the clinical picture and describe the natural history of chronic disease.
  7. 7. To provide clues to causes.

These uses are relevant not only to efforts to combat disease and disability, but also to parallel efforts to eradicate the many social problems that play a major role in creating the conditions in which disease and disability thrive and hamper our efforts to prevent and control them. Indeed, it is a vicious circle because disease and disability  ̶ inappropriately attended and controlled  ̶ perpetuate and exacerbate social problems and vice versa.

A careful discussion of the relationship between mental health and drug abuse epidemiology requires more time than I have available to me in the closing minutes of this conference. Basic to such a discussion are operational definitions of drug abuse and mental health. These are needed to specify types of relationships, study designs for elucidating the relationships, and data collection instruments and procedures for acquiring the data needed to compute the various indices. Since the types of relationships to be considered have not been specified, I will suggest a few that might be considered.

For this illustration, I will assume the following: (a) the operational definition of drug abuse has been agreed upon; (b) a subgroup of drug abusers are persons who would be classified as drug dependent; (c) the definition of drug dependence is that given in the American Psychiatric Association’s (APA) manual on Mental Disorders (DSM-II) which includes dependence on such substances as opium, opium alkaloids, synthetic analgesics, barbiturates, cocaine, cannabis sativa, amphetamines and other psychostimulants; (d) the mental disorders other than “drug abuse” are those defined in the APA Manual (DSM-II) . The problem before us then is to investigate certain relationships between the occurrence of drug dependence and mental disorders other than drug dependence in a defined population of persons. Let us specify that we have a catchment area of population size N and we wish to classify its residents on two major axes: (1) Presence or absence of mental disorders other than drug dependence; and (2) presence or absence of drug dependence as in the following four-fold table.

To proceed further, it is necessary to specify the types of questions to be answered from this table. If we are merely after a point prevalence count, i.e., the number of persons as of a specified date (given point in time) who have a specified characteristic, then we would need case finding procedures for determining which of the residents fall in each of the cells of the above fourfold table. It would then be possible to determine the proportion of the population of the catchment area as of a given date (e.g., July 1, 1974) that are: (a) both drug dependent and have another mental disorder; (b) drug dependent only; (c) with other mental disorder only; or (d) neither drug dependent nor with other mental disorder. The marginal totals provide the data needed to provide the point prevalence rates of drug dependence and other mental disorders. This is only one type of prevalence count. Other types of prevalence questions might be asked. For example, how many residents of the catchment area have bad an episode of drug dependence and/or mental disorder in the past 12 months? Answers to such a question provide the interval prevalence rate; i.e., the number of persons who have experienced episode(s) of illness (es) any time during the past 12 months. This is called an interval prevalence rate, i.e., the proportion of the population who have experienced an episode of illness at any time during an interval of time.

The above prevalence measures (point or interval) can be computed specific for age, sex, race, type of mental disorder, type of substance on which the person is dependent, marital status, living arrangements, etc.

Referring again to the four-fold table, we can ask other questions. What is the prevalence of drug dependence among persons known to be: (a) schizophrenic; or (b) to be suffering from a major affective disorder, i.e., manic depressive disorder (bipolar depress ion), manic dissorder only, or depressive disorder only (unipolar depression)?

Or, given persons known to be drug dependent, what is the prevalence of organic brain syndromes among them?

Still other questions can be asked, such as: given persons who have a major affective disorder but are not drug dependent as of the survey date, what is the incidence rate of drug dependence within some defined period of time, e.g., one year following that date. That is, how many persons with a specified mental disorder become drug dependent for the first time during a defined interval of time?

We can also raise questions about the extent to which persons in the cells of the above four-fold table are receiving services either for their drug dependence, their other mental disorder, or both. Are these services being rendered by personnel in a single facility? Are these services being coordinated? Or, how many persons receive services for drug problems in one facility and services for schizophrenia in another facility? Again, are these services being coordinated?

Many questions can be asked relating to the incidence and/or prevalence of various physical illnesses; e.g., cancer, cardiovascular diseases, tuberculosis, nutritional deficiencies, accidents, suicide among persons who are classified as drug dependent. Or, vice versa, i.e., how persons with a specified illness became drug dependent.

Since the interrelationships that can be investigated are many, I would urge that, if we are serious about exploring them, and I hope we are, then a committee should be established to specify the important questions to be answered about the reciprocal relationships between drug dependence and other types of mental disorders, the types of services required by these persons, the extent to which they are receiving them, and their effectiveness.

Persons doing field surveys and evaluative studies related to mental disorders have developed case finding techniques, designs for evaluation of effectiveness of services, etc. Persons working in the drug abuse field have developed techniques for similar purposes. A mechanism is needed to assure that there is a frequent interchange of information among these investigators. To illustrate, the Division of Biometry has developed a demographic profile system which provides for each of the 1,500 mental health center catchment areas (established in the U.S. under the community mental health centers regulations) a series of 107 social indicators. These indicators define types of high risk population for mental health, other health and social problems. Certainly, such data should be of value to persons planning drug abuse services. In addition these population data provide denominators for a whole series of morbidity rates. What we lack are the numerators. Indeed, a major problem that must be resolved to carry out the types of research specified above revolves around the development of reliable, valid, sensitive and specific case finding procedures for drug dependent persons and for persons who have mental disorders (e.g., schizophrenia, affective disorders, psychoneuroses, organic brain syndromes, etc.). Another illustration of work going on in the mental health area is a study which the Biometry Division is funding jointly with with in New York State. ‘The Director of Statistical Services for the NYS Department of Mental Hygiene is studying the patterns of use of services for mental health, alcoholism and drug abuse in a selected number of catchment areas in the State ranging from very rural to highly urbanized populations and relating the use patterns to demographic variables and diagnosis and to service networks available in each area.

I would urge that we pool our knowledge and experience to develop a series of studies that would be mutually beneficial. From what I have heard today, you have acquired extensive experience in community surveys. I would hope that, in the future, those of you conducting such surveys might find it possible to add to your instruments questions that would be of value to those of us who are concerned with the epidemiology of the other mental disorders and planning programs for the delivery of services to prevent and control disability associated with these disorders and evaluating their effectiveness.

In the mental health field, we have developed a body of techniques for collecting and analyzing data for monitoring the delivery of mental health services. Those of you actively involved in delivering services to drug abusers and drug dependent persons have developed similar techniques for monitoring and evaluating these services. I would urge that we pool our knowledge. This can only be done by developing collaborative arrangements for exchange of information and mechanisms for planning studies that will investigate the many inter – relationships between mental disorders and drug dependence and the delivery of services to the persons suffering from these disorders.

Morton Kramer, Sc.D.

Selections from the book: “The Epidemiology of Drug Abuse: Current Issues”. Louise G. Richards, Ph.D., and Louise B. Blevens, editors. Conference Proceedings. Examination of methodological problems in surveys and data collection. National Institute on Drug Abuse Research Monograph 10, March 1977.