But for some diseases, it does seem that the ritual of treatment affects the way we feel.
Ferzaan Engineer, the boss of Quintiles's venture, says that for some diseases this can dramatically cut the time needed to bring new therapies to market.
It notes the benefits of breastfeeding include protection for the baby from certain infections, and for the mother from some diseases in later life.
The report, which was commissioned in January 1997 by the White House Office of National Drug Control Policy, looked at the effects of smoked marijuana on all the diseases for which some consensus exists that it might be beneficial.
Patient populations for these diseases are tiny, some as few as 1, 100 patients.
This has the enormous potential to empower scientists and clinicians to achieve better and more affordable diagnosis and cure for some of the most devastating and challenging diseases and to accelerate the progress made in this field.
Already, Alzheimer's and other diseases of old age account for some 70% of health-care reimbursements.
But in some cases, as with drugs for rare diseases or studies done in children, the FDA will lengthen this exclusivity, or grant it where no patent exists.
Unlike some other diseases, however, clear genetic markers for coronary heart disease, which accounts for 1 in 6 U.S. deaths, remain elusive.
Auto-immune diseases are caused when the immune system, for some reason, decides that a certain type of the body's own cells are foreign and starts attacking them.
Scientists and even some anti-abortion rights Republicans are urging the president to finance experiments on stem cells from human embryos, charging the research could lead to revolutionary treatments for diseases such as Parkinson's, diabetes and some forms of cancer.
It is going to be extremely difficult to find the cures for big diseases like cancer unless we start to get hold of some of this information.
Dr. Sanjay Gupta, CNN chief medical correspondent: We've known for some time that exposing kids to germs reduces their likelihood of developing diseases such as asthma and diabetes.
While representing only 1 percent of the FTC's 2012 survey, the personal cost is multi-faceted and, like some diseases, the residual effect of a fraudulent invasion can last for many years.
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In addition, emerging research shows a possible role for vitamin D in the prevention or treatment of type 1 diabetes, some cancers, and autoimmune diseases including multiple sclerosis.
Mr Obama repeated the claims of some scientists that embryonic stem cell research could lead to a cure for a whole host of diseases like Parkinson's, Alzheimer's and diabetes and that it could even help someone who is paralysed to walk again.
Enbrel is now in tests for two dozen other diseases, from chronic heart failure to psoriasis to Alzheimer's and even some cancers.
By the 1980s vaccines had wiped out so many diseases, and vaccine prices had fallen so far, some companies gave up searching for new ones.
The problem is that vaccines for other diseases work by stimulating in everybody a disease-clearing immune response that is already present in some.
For example, in Germany and the Netherlands some insurers have started to negotiate special deals with providers that make the management of chronic diseases easier for patients.
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It is thought that some of the rare tropical diseases may have emerged from the forests of Africa where they have been harboured for thousands of years by species that would previously not have come into contact with humans.
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