Off-label, both Nuvigil and its predecessor Provigil may be used for a number of conditions. These can include residual fatigue after antidepressant treatment in patients with Major Depressive Disorder, fatigue caused by the nerve disease multiple sclerosis, and the extreme fatigue associated with fibromyalgia and chronic fatigue syndrome. Physicians may treat fatigue associated with many other conditions with Nuvigil, as well. There are insufficient studies about the effectiveness of modafinil for these conditions, however. It is unknown whether armodafinil would be more effective than modafinil for these causes of fatigue.
In some studies, modafinil has been shown to be effective in both children and adults in the treatment of attention-deficit hyperactivity disorder (ADHD), with effects about equal to the commonly-used stimulants methylphenidate (Ritalin, Metadate, Concerta, and others) and amphetamines (Adderall, Dexedrine, Vyvanse, and others). It is not approved as an ADHD treatment, however, due to concerns about its safety, especially for children and adolescents.
Modafinil has also successfully treated bipolar depression, a notoriously difficult condition to treat. It should only be used in bipolar patients in whom stimulants do not trigger mania.