People with MS naturally ask their physicians how the disease will affect them. However it’s impossible to give useful information about the long-term outlook immediately after the diagnosis, because MS varies from one person to the next and within one person over time. After about five years, physicians have a much better idea how the disease will evolve. Generally, the progress of the disease breaks down into the Rule of One-Third: One-Third of people with MS do very well-their condition is sometimes called “benign MS”–one-third do moderately well and one-third are significantly disabled. Twenty years after diagnosis, about a sixth are in a wheelchair and half require some assistance with walking, be it cane, walker or wheelchair. Twenty-five years after diagnosis, two-thirds are still able to walk, although some need a cane or a walker and one-third use a wheelchair most of the time. Remember that MS comes in two main forms: Relapse-Remitting and Progressive. Because treatment is determined by the kind of MS you have, it’s important to ask your neurologist which of the four categories-clinically isolated, relapse-remitting, primary progressive or secondary progressive-you are dealing with. At any given moment, about half of MS patients have relapsing-remitting MS and the other half have progessive MS. Relapsing-remitting disease can be highly variable. Progressive disease can be progressive right from the start (primary progressive) or can become progressive after being relapsing-remitting for many years. Progressive MS, of course, implies a progressive increase in disability. However, MS does not progress endlessly. After a variable length of time it usually plateaus, with no significant increase in disability. People with progressive MS are more likely to need a wheelchair and to have significant neurological disability. People who have remissions from their attacks usually have mild to moderate disability. A number of other factors affect the prognosis. Perhaps most important are the specific symptoms you have. If they relate mainly to sensations such as feeling or vision, disability is usually moderate to mild. If the main symptoms are limb weakness and loss of coordination, you are more likely to become disabled eventually. Frequent attacks and failure to improve after attacks also suggest eventual disability. In general, men with MS do worse than women with MS. No one knows why. Also, the later in life you come down with MS, the faster the neurological symptoms tend to get worse. The most significant indicator of the prognosis course is whether your condition is progressive, as a progressive course implies a greater degree of neurological disability. Progressive MS tends to develop at the same rate regardless of whether it is primary progressive or secondary progressive. These two are best thought of, not as different categorizations of MS, but simply as differnt stages. To date, the MRI scan, evoked potentials test and spinal fluid examination can’t predict the future with any accuracy. Refinements in our understanding of prognostic factors are allowing us to pick out some of the people who need more aggressive (and potentially risky) treatment, such as chemotherapy or bone marrow transplantation. Maybe the most important point about the prognosis in MS is that it is not as bad, on average, as most people think. We tend to notice the people who are most disabled by MS. Yet many people–co-workers, friends, relatives–live completely normal, full lives, with little or no visible disability.