Anticonvulsant derivatives useful in treating post traumatic stress disorder

A method for treating post traumatic stress disorder, comprising administering to a mammal afflicted with such condition a therapeutically effective amount for treating such condition of a compound of the formula I:

• wherein
• X is CH2 or oxygen;
• R1 is hydrogen or alkyl;
• and
• R2, R3, R4 and R5 are independently hydrogen or alkyl and, when X is CH2, R4 and R5, may be alkene groups joined to form a benzene ring and, when X is oxygen, R2 and R3 and/or R4 and R5 together may be a methylenedioxy group of the following formula(II):
• wherein
• R6 and R7 are the same or different and are hydrogen, or alkyl and are joined to form a cyclopentyl or cyclohexyl ring.