In An Unquiet Mind by Redfield Jamison, does the author make the point that mental illness is very common? Are there are any quotes to support this? I know she emphasizes treatment and medicine, but does she clearly make the point that mental illness is much more common than people think (that many more people are affected than was thought)?

Redfield Jamison makes the point that mental illness is very common. For example, she writes that women are often not diagnosed with mania because depression is "more in line with society's notions of what women are about: passive, sensitive, hopeless, helpless, stricken..." (page 123). However, she writes that while depression is twice as common in women as in men, "manic-depressive illness occurs equally often in women and men, and, being a relatively common condition, mania ends up affecting a large number of women" (page 123). In other words, while women are not perceived as having mania, many of them do, as mania is very common.
She later writes that it might be impossible to split mood disorders into manic and depressive states and that such a distinction "minimizes the importance of mixed manic-and-depressive states, conditions that are common, extremely important clinically" (page 183). In other words, mania and depression are often mixed, and these conditions are very common.
The author also writes about the increased public knowledge of mental disorders and the fact that mental health advocacy groups have increased support for people with mental illness and their families by convincing members of Congress, "many of whom themselves suffer from mood disorders or have mental illness in their families" (page 184). The author notes that many public figures have mental illnesses, including mood disorders, as do many people in society. People and their families often suffer from mental illness as a result.