The present invention relates to compositions that can be used, for example, in methods of treating medical conditions and symptoms associated with brain dysfunction, including but not limited to Gulf War illness (GWI), multiple chemical sensitivity (MCS), cognitive dysfunction (CD), multiple sclerosis (MS), and neurological disorders such as amyotrophic lateral sclerosis (ALS). in various embodiments, the compositions of the invention, which can. be administered or prepared as a medicament for use in the treatment methods described herein, are phthalazinediones or pharmaceutically acceptable salts thereof. As described further below, the phthalazinedione can be 5-amino-2,3-dihydro-1；4-phthala2:inedion.e； an analog or variant thereof； or a salt of the specified compound, the analog, or the variant. The compounds described herein can be formulated as diagnostic or pharmaceutical compositions, and the invention features kits including one or more of these compounds.
