Once upon a time, paediatrics was involved with infectious disease and acute disorders, but a new pattern of morbidity has emerged. Social difficulties, behavioural problems, developmental difficulties, disabilities and chronic disease have become main parts of the scope of paediatric practice. Among adults, multiple chronic disease is increasingly prevalent, whereas the prevalence of impairment and disability remain stable, but substantial and therefore, present day health professionals must be aware of disability and chronic disease. Just a few decades ago, children born with significant congenital anomalies or genetic and metabolic diseases perished at an early age and very few survived into their teens and even less into adulthood. Congenital heart disease, major errors in metabolism, cancer, cystic fibrosis and many other major diseases were fatal. Because of that, many physicians in adult primary care did not have the opportunity to see patients with these problems and thus were unable to learn how to care for them. With major advancements in medical knowledge, technology, imaging techniques, surgical skills and pharmaceutical products as well as prosthetic devices, many of these patients now live much longer lives and sometimes even close to the average life expectancy for the country, at least in the developed world. With that, a new medical care challenge has been created and we have to take a life span approach.

Mental health is "a state of well-being in which the individual realises his or her own abilities; can cope with the normal stresses of life; can work productively and fruitfully; and is able to make a contribution to his or her community". Mental illness is defined as "collectively, all diagnosable mental disorders" or "health conditions that are characterised by alterations in thinking, mood, or behaviour (or some combination thereof) associated with distress and/or impaired functioning." Mental disorders, especially depressive disorders, are related to many chronic diseases like diabetes, cancer, cardiovascular disease, asthma and obesity. In recent years, there has been an alarming number of school shootings with youth or adults involved who are seriously mentally disturbed. There has also been an increase in suicides and mental pathology in the military and in fact, many professionals perceive that the increase in psychiatric drugs negatively impacts our population. In spite of more people receiving psychotropic medication at a large expense to the individual and society, it does not seem that people are getting better on the whole. As a result, there is a need to re-evaluate our policy and interventions, but also a need for more accurate data and information.