Universal prevention has been a focus of psychiatric research for the past 4 decades. Using a public health approach, research has shown that mitigating major risk factors, such as poverty and early life stress, and promoting protective factors can improve behavioral outcomes. In other areas of medicine, we have observed how similar preventive approaches have reduced deaths from cancer and infectious disease. By contrast, while reducing environmental stress and providing better maternal support improve general behavioral outcomes (by preventing the development of antisocial behavior, for example), there are few, if any, examples of preventive approaches in psychiatry that reduce either the morbidity or the mortality of our most disabling illnesses—such as schizophrenia and bipolar disorder.1,2
What can be done to improve the impact of preventive interventions in psychiatry? Do we have effective preventions that are not being implemented? Or do we need new approaches
to reduce morbidity and mortality? While we certainly can do much more to implement what we already know, it may soon be time for us to consider a shift from universal prevention provided in the broad population to “preemptive” approaches. Preemptive interventions target those at greatest risk for mental illness and those with subdiagnostic signs or symptoms, and they provide what previously has been labeled “selective” and “indicated” prevention.3
This preemptive approach in medicine is emerging as the focus of health care shifts from acute to chronic disorders. Until recently, our approach to most medical disorders was based on the infectious diseases of the 20th century, acute illnesses with a rapid onset that could be prevented by such universal approaches as vaccination and vector eradication. This model may not suffice for the chronic diseases, which will be the preoccupation of health care in the 21st century. While eliminating general risk factors, such as smoking and obesity, remains a goal in the prevention of chronic diseases, increasingly we recognize the need to identify individual patterns of risk so that preemptive interventions can be directed to those at greatest risk.
A trajectory model will be critical, recognizing that chronic disorders evolve for years or even decades before they are diagnosed in their late stages (for example, dementia or psychosis). Atherosclerosis is an instructive example: a disease that used to be diagnosed in its end stage as myocardial infarction is now diagnosed years earlier based on a range of individual risk factors (family history, plasma lipid levels, electrophysiology, and imaging results) and treated with diet, exercise, and medication to preempt ischemic damage.
Virtually all mental disorders are chronic disorders. Moreover, the National Comorbidity Survey Replication further demonstrated that mental disorders are the chronic disorders of youth.4 Could we approach schizophrenia, mood disorders, and anxiety disorders with preemptive strategies? The answer requires 2 kinds of progress:
• Understanding patterns of risk that predict disorder for an individual.
• Developing effective interventions for preemption.
How far are we from these 2 goals for mental disorders?
We do not have biomarkers for early detection of any mental disorder. We do, however, know a number of risk factors for each of the common mental disorders. Depending on the disorder, family history, childhood history, and previous psychopathology are significant predictors.
A few examples may help illustrate this point. Children who have been severely abused physically or sexually have more than twice the risk of developing major depressive disorder.5 Those who have made a suicide attempt are at a 40-fold increased risk of dying from suicide.6 And as many as 80% of adolescents in whom a psychotic disorder will eventually develop can be identified when the disease is in the prodromal stage—before the onset of psychosis—on the basis of subacute clinical symptoms, family history, and dramatic changes in social functioning.7 Genetics will likely provide a new generation of factors that will be added to the assessment of risk. As with heart disease and cancer, it is likely that individual risk for any specific mental disorder will be determined by a combination of factors, rather than by a single biomarker. One can imagine a time in the not-too-distant future when a 15-year-old with a family history of schizophrenia or bipolar disorder could be assessed with cognitive, genetic, and imaging tests to diagnose the early stages of schizophrenia or bipolar disorder well before a psychotic episode.
