Health insurance is insurance that covers the whole or a part of the risk of a person incurring medical expenses, spreading the risk over a large number of persons. By estimating the overall risk of health care and health system expenses over the risk pool, an insurer can develop a routine finance structure, such as a monthly premium or payroll tax, to provide the money to pay for the health care benefits specified in the insurance agreement.[1] The benefit is administered by a central organization such as a government agency, private business, or not-for-profit entity.
Private health care has continued parallel to the NHS, paid for largely by private insurance, but it is used by less than 8% of the population, and generally as a top-up to NHS services. There are many treatments that the private sector does not provide. For example, health insurance on pregnancy is generally not covered or covered with restricting clauses. Typical exclusions for Bupa schemes (and many other insurers) include:

Recently (2009) the main representative body of British Medical physicians, the British Medical Association, adopted a policy statement expressing concerns about developments in the health insurance market in the UK. In its Annual Representative Meeting which had been agreed earlier by the Consultants Policy Group (i.e. Senior physicians) stating that the BMA was "extremely concerned that the policies of some private healthcare insurance companies are preventing or restricting patients exercising choice about (i) the consultants who treat them; (ii) the hospital at which they are treated; (iii) making top up payments to cover any gap between the funding provided by their insurance company and the cost of their chosen private treatment." It went in to "call on the BMA to publicise these concerns so that patients are fully informed when making choices about private healthcare insurance."[50] The practice of insurance companies deciding which consultant a patient may see as opposed to GPs or patients is referred to as Open Referral.[51] The NHS offers patients a choice of hospitals and consultants and does not charge for its services.

Mental illness is described as 'the spectrum of cognitive, emotional, and behavioral conditions that interfere with social and emotional well-being and the lives and productivity of people. Having a mental illness can seriously impair, temporarily or permanently, the mental functioning of a person. Other terms include: 'mental health problem', 'illness', 'disorder', 'dysfunction'.[38]
Some, if not most, health care providers in the United States will agree to bill the insurance company if patients are willing to sign an agreement that they will be responsible for the amount that the insurance company doesn't pay. The insurance company pays out of network providers according to "reasonable and customary" charges, which may be less than the provider's usual fee. The provider may also have a separate contract with the insurer to accept what amounts to a discounted rate or capitation to the provider's standard charges. It generally costs the patient less to use an in-network provider.
Generally, the context in which an individual lives is of great importance for both his health status and quality of their life[18]. It is increasingly recognized that health is maintained and improved not only through the advancement and application of health science, but also through the efforts and intelligent lifestyle choices of the individual and society. According to the World Health Organization, the main determinants of health include the social and economic environment, the physical environment and the person's individual characteristics and behaviors.[19]
In 2013 a state funded private care insurance was introduced ("Private Pflegeversicherung").[37] Insurance contracts that fit certain criteria are subsidised with 60 Euro per year. It is expected that the number of contracts will grow from 400,000 by end of 2013 to over a million within the next few years.[38] These contracts have been criticized by consumer rights foundations.[39]

The meaning of health has evolved over time. In keeping with the biomedical perspective, early definitions of health focused on the theme of the body's ability to function; health was seen as a state of normal function that could be disrupted from time to time by disease. An example of such a definition of health is: "a state characterized by anatomic, physiologic, and psychological integrity; ability to perform personally valued family, work, and community roles; ability to deal with physical, biological, psychological, and social stress".[7] Then in 1948, in a radical departure from previous definitions, the World Health Organization (WHO) proposed a definition that aimed higher: linking health to well-being, in terms of "physical, mental, and social well-being, and not merely the absence of disease and infirmity".[8] Although this definition was welcomed by some as being innovative, it was also criticized as being vague, excessively broad and was not construed as measurable. For a long time, it was set aside as an impractical ideal and most discussions of health returned to the practicality of the biomedical model.[9]