Lability n. : Liability to lapse, err, or apostatize.

Example:
Can lamictal cause mood Lability?

Taxonomy
Lability, Labile affect, free encyclopedia, Search, cells divide, Wiktionary, free dictionary, Proteins, cell cycle, stable, epithelium, cornea, Chemistry, Metalloprotein, PubMed Central, Biochem, psychological term, Biology.

Defination from the web:
lability in Wiktionary, the free dictionary. Lability refers to something that is constantly undergoing change or something ... adopting a lower energy conformation, the former molecular structure is said to have 'high lability' (such as C25, a 25-carbon fullerene spheroid) ...