Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
claustrophobic [klɔːstrəˈfəubɪk] adj
she is claustrophobic она́ страда́ет клаустрофо́бией, у неё клаустрофо́бия
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.