can lead to hypertension; however, it can also lead to coronary heart disease. It is nearly impossible to tell which path will be taken as a result of the stress, and it could result in both. Base rate problem This problem states that it is very hard to predict whether the presence of a stressor will lead to the development of a disorder. The reason behind this is that experiencing the environmental stressor may lead to developing the disorder. However, diagnosing a patient on this alone would result in an absurd amount of false positives. An example of this would be smoking and cancer. If doctors were to diagnose everyone who ever smoked a cigarette or a cigar with cancer it would quickly become apparent that it is an ineffective diagnostic criterion because many individuals would not develop lung cancer. Holistic method The main premise of the biopsychosocial model is that you cannot separate the biological factors from the environmental factors when addressing an illness; you must view a person as part of a whole, or a system. The system theory is one of the best methods in which to observe this holistic model. The systems theory states that an individual exists within a hierarchy of subsystems (e.g. cells, person, family, society, etc.), and all of these subsystems interact. For example, if one were to lose a family member the individual may feel stressed which in turn may weaken his immune system and cause him or her to catch a cold. While the cold is considered biological in nature (i.e. a bacterium or a virus), it was aided by outside factors. This is a great example of how the biopsychosocial model approaches medical conditions. In order to effectively assess an illness one must identify and treat all contributing factors as well as the actual biological factors. This need to address physical, mental, and social needs (among many others) lead to health psychology, and from this the field of pediatric psychology. Origins World War II gave way to a rise in the amount of psychologists that worked in medical schools. The pediatric population doctors worked with had a variety of problems in addition to their illnessDoctors had children as patients with a variety of problems (e.g., developmental, behavioral, academic). Patients needs, and their families, were not receiving adequate attention from psychology clinics at the time. To meet the needs of pediatric