Primary prevention of mental disorders
J. M. Bertolote
Despite the demonstration of the possibility of preventing some forms of mental disorders, many mental health professionals continue to underestimate the possibilities of primary prevention in their field. This is due to:
1 a lack of clear concepts when referring to this issue;
2 the fact that the effective prevention of mental and neurological disorders often falls outside the usual remit of mental health professionals (in many cases it falls outside the health sector altogether).
These two factors are discussed below, in addition to an indication of actions which effectively prevent some forms of mental disorders.
Prevention
In the late 1950s, Leavell and Clark(1) proposed a three-level concept of prevention (primary, secondary, and tertiary), covering almost all medical actions. Their innovative approach must be understood in relation to what they also called the horizon of the natural history of the disease process: under natural circumstances, a disease will proceed from a prepathological period through its early stages, evolving either to partial or full recovery (or cure), or to death; in the case of partial recovery, there may be chronification or sequelae. Prevention, in this sense, refers not only to the appearance of the disease but also to any further worsening or complication of it once it has appeared.
Primary prevention
The primary prevention level covers what is otherwise referred to as both health promotion and specific protection, and is best exemplified by, for example, adequate nutrition and immunization against specific diseases by vaccines. Whereas, in this example, adequate nutrition is totally non-specific (it contributes to enhancing the overall resistance to several diseases without conferring any specific protection against any), vaccination is highly specific in relation to a single condition. Rational-specific protection is fully dependent on a reasonable knowledge of the aetiology of the disease (or, at least, its mode of transmission) in order to be effective.
Secondary prevention
The secondary prevention level refers to early detection and treatment of diseases. Usually the bulk of the medical activity, its main preventive goal is to avoid chronicity and the establishment of irreversible sequelae. It is dealt with more specifically in Part 6 of this book.
Tertiary prevention
The tertiary prevention level largely corresponds to rehabilitation. It enters into operation once the disease process has been established and aims at reducing as much as possible damages caused by the disease process, preserving intact functions, and restoring and/ or compensating impaired functions, disabilities, and handicaps.
On one hand, this conceptual model was highly instrumental in providing an impetus towards preventive activities in the medical field as a whole but, on the other hand, it so popularized the term prevention that it almost lost its powerful message. Therefore, it is important to retain the idea of primary prevention as a synonym of specific protection, referring to methods designed to avoid the occurrence of a specific disorder or groups of disorders. It comprises those measures applicable to a particular disease or group of diseases in order to intercept their causes before they affect people, and should be differentiated not only from treatment and rehabilitation, but also from mental health promotion.
The main obstacle for the prevention of many mental disorders is the limited knowledge about their aetiology. Admittedly, there are very promising and exciting hypotheses concerning the causes of three mental disorders which represent the greatest burden, namely, depression, schizophrenia, and dementia. They are, nevertheless, nothing more than hypotheses. The most successful examples of prevention of diseases refer to those whose aetiology (cause and/or mode of transmission) is relatively well-known. There are historical examples of the prevention of some conditions based on false assumptions about or without a good knowledge of their aetiology (for example, the eradication of malaria in ancient Rome, and the control of the London cholera epidemics by John Snow in the nineteenth century). However, it does not seem appropriate for health professionals and scientists to base their actions on chance or false assumptions, even though the result might be opportune to the population.
As implied by the need to intercept causes of a particular disease or groups of diseases (with a common cause), the concept of prevention calls for a high degree of specificity concerning the target condition or conditions. In the medical field, it led to successful programmes for the prevention of, for example, diarrhoeal diseases (such as typhoid), hypertension, coronary heart disease, breast cancer, and unwanted pregnancies, rather than of infectious diseases, cardiovascular diseases, cancer, or obstetrical problems. Unfortunately, in the mental health field there has not been a great concern with the specification of the target condition, and the prevention of ‘mental disorders’ (as a whole) became a label soon associated with failure and disinterest.
Mental disorders
What is understood as ‘mental disorders’ comprises a variety of quite diverse clinical conditions in terms of aetiology, symptomatology, clinical course, prognosis, and response to treatment. Therefore, whenever the prevention of mental disorders is referred to, an effort must be made to obtain some precision.
From a nosological point of view, most of the mental disorders are conceptually at a syndromal level; depression, schizophrenia, and dementia are appropriate examples. In this respect, dementia is one step ahead of the other two, in so far as vascular dementia is now clearly differentiated from Alzheimer’s disease, with important implications for prevention.
Therefore a strategic shift is necessary in order to obtain greater efficiency in the successful prevention of some mental disorders. The first step is for an effort to be as specific as possible in relation to the target condition: for instance Down syndrome or phenylketonuria instead of intellectual disorder, foetal alcohol syndrome, delirium tremens instead of alcoholism, and vascular dementia and dementia following brain injury instead of dementia in general.
The second step applies to those conditions which cannot be meaningfully broken down into more specific conditions, such as schizophrenia or depression. In these cases, the target is displaced from the appearance of the conditions towards future relapses, once a first episode has occurred; this conveniently applies to schizophrenia, depression, and dependence on alcohol and other drugs.
Finally, there are some violent behaviours, such as suicide, parasuicide, and violence against others, the control (and prevention) of which are largely expected by society to come from the field of mental health. They do not characterize a mental disorder in particular, but are frequently associated with one or more of them. Their prevention, therefore, requires specifically dedicated interventions.
With this wide range of issues considered as mental disorders, it becomes clear that the coverage of their prevention goes well beyond the limits of this chapter. A detailed conceptual approach to the prevention of mental and psychosocial disorders can be found in a recent publication of the World Health Organization (WHO).(2)
Prevention of mental disorders
From a practical point of view there are three groups of conditions for which efficient preventive action has been documented.
1 Mental disorders with known aetiology: this mostly includes those disorders demonstrated to have an organic basis, ranging from the ‘historical’ general paresis and dementing disorders (e.g. vascular dementia, pellagra, and dementias associated with infectious and parasitic diseases such as malaria and HIV infection) to several forms of intellectual disorder (Down syndrome, foetal alcohol syndrome, phenylketonuria, and intellectual disorder due to iodine deficiency).
2 Mental disorders without a well-established aetiology but with a relatively predictable course: these are chronic disorders with a recurrent relapsing fluctuating pattern, such as schizophrenia, mood disorders (unipolar and bipolar), and alcohol dependence syndrome.
3 Psychosocial problems strongly associated with mental disorders: these range from violence (domestic and other) to suicide and staff burnout.
Mental disorders with known aetiology
(a) Infectious diseases
Prevention of this group of disorders has by far yielded the greatest success. The demonstration in 1911 by Noguchi and Moore of the brain infection by Treponema pallidum as the cause of general paresis(3) opened the way in 1917 to its treatment by malaria therapy, and later to its prevention with penicillin; this is now a landmark in the history of medicine. The discovery of the aetiology of pellagra also led to its prevention and control, leading to the prevention of one type of dementia associated with alcoholism and avitaminosis.
These two once very frequent diseases have almost completely disappeared and there are many experienced psychiatrists who never come across a single case of either; with them also disappeared the history of their successful control. Although the same success has not yet been achieved in relation to vascular dementia, the control of hypertension and atherosclerosis (e.g. through the reduction of salt and fat intake) can significantly reduce brain damage and ensuing dementia (vascular or multi-infarct dementia).
In some developing countries, meningitis and malaria (and, to a lesser extent, inadequately treated epilepsy) are important causes of permanent brain damage which can also lead to dementing disorders. The environmental control of malaria and other brain infections, of which bacterial meningitis is the most important, and their early and prompt treatment can reduce the impact of the infection on the brain and prevent these forms of dementia (or intellectual disorder, depending on the age of onset).
More recently, it has been demonstrated that in some people infected with HIV, the initial manifestations of AIDS are accompanied by some forms of mental disorder, such as mood disorders or dementia.(4) The prevention of these forms of mental disorders follow the same measures as for the prevention of AIDS in general. However, it is not yet certain if the newer combined treatments (bi- and tritherapy) can alter the course of AIDS when brain damage due to HIV has been confirmed.
(b) Intellectual disorder (mental retardation)
Up to 15 per cent of cases of intellectual disorder could be prevented by dealing with the causes that lead to it. A recent WHO publication(2) has set detailed guidelines for the prevention of some forms of this condition, namely, Down syndrome, foetal alcohol syndrome, phenylketonuria, and iodine deficiency syndrome.
These preventive actions are both efficient and affordable even in very poor regions of the world.
These preventive actions are both efficient and affordable even in very poor regions of the world.
Down syndrome—The primary prevention of Down syndrome can be successfully achieved through the control of the age at which women become pregnant: ideally, the age range during which the risk is minimal is between 16 and 35 years, after which the risk increases almost exponentially, as shown in Fig. 7.4.1. Amniocentesis is a procedure that can be very useful for the in utero diagnosis of Down syndrome (as well as of other problems and malformations). Where it is culturally and morally acceptable, and legally permitted, a therapeutic abortion is viewed by some as another primary prevention measure.
Iodine deficiency—The world population at risk of intellectual disability due to iodine deficiency is approximately 1 billion and it still occurs in large numbers in some regions of the globe.(6) However, it can be very efficiently and cheaply prevented through the addition of iodine to salt, milk, flour, or water, or, in special situations, through injections of an oily solution containing iodine.(7)
Phenylketonuria—Intellectual disorder due to phenylketonuria can also be successfully prevented through the early identification of children at risk who then receive a phenylalanine-free diet throughout their lives.(8)
Foetal alcohol syndrome (FAS)—Intellectual disorder and malformations seen in FAS syndrome can be prevented if women stay away from alcohol during pregnancy, more particularly during the first trimester, or at least keep their alcohol intake below the dangerous limit of 15 g of ethanol per day.(9)Related posts:
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