Intoxication:  GABAnergic agents, benzodiazepines cause an intoxication similar to alcohol with drowiness, lethargy, ataxia, decreased anxiety (except for paradoxical disinhibition), and sometimes confusion.  They rarely cause respiratory depression, but when combined with alcohol can be lethal.

Withdrawal:  similar to alcohol, but also includes anxiety, numbness in the extremities, dysphoria, intolerance of bright lights and loud noises, nausea, and sometimes convulsions as well as muscle twitching.  To prevent withdrawal, GRADUALLY reduce the dose, perhaps 10-15% a week for someone who has been using the equivalent of 40 mg po qd of diazepam on a daily basis.  (Kaplan, 5th edition, 231)