Clinical Textbook of Addictive Disorders 3rd ed - R. Frances, S. Miller, A. Mack (Guilford, 2005) WW

230 III. SUBSTANCES OF ABUSEAlthough a long half-life may be beneficial in reducing the speed of onsetand severity of benzodiazepine withdrawal on abrupt discontinuation, it can bemore problematic in other situations. An increase in motor vehicle crashinvolvement was found in elderly persons using long half-life benzodiazepines,whereas use of shorter half-life benzodiazepines showed no increase in the probabilityof crashes in elderly persons compared to same-age persons who did notuse a benzodiazepine (Hemmelgarn, Suissa, Huang, Boivin, & Pinard, 1997;Wang, Bohn, Glynn, Mogun, & Avom, 2001).ReinforcementThree additional aspects of benzodiazepine pharmacology are relevant to thetreatment of addicted patients: reinforcement, withdrawal, and tolerance.Reinforcement is the potential for these medicines to be abused or “liked” byalcoholics and drug addicts. In controlled studies, benzodiazepines are not reinforcingor “liked” by either normal or anxious subjects. For example, normaland anxious subjects, given a choice between placebos and benzodiazepines,more often choose the placebo in double-blind acute dose experiments, regardlessof the specific benzodiazepine given. In contrast, subjects with a history ofaddiction in double-blind studies prefer benzodiazepines—especially at highdoses—to placebos. Studies have demonstrated that people with a history ofaddiction show a greater preference for intermediate-acting barbiturates andstimulants, as well as narcotics, than for benzodiazepines. Thus, the benzodiazepinesare reinforcing for alcoholics and drug addicts (though not for anxiouspeople or for people who do not have a history of addiction). The benzodiazepinesare relatively weak reinforcers compared to opiates, stimulants, andbarbiturates among alcoholics and drug addicts.This research confirms the common clinical observation that benzodiazepinesare rarely drugs of choice among addicted people for their euphoriceffects (DuPont, 1984, 1988). Although it remains unclear why alcoholics anddrug addicts react differently to the benzodiazepines than do normal or anxioussubjects, this phenomenon exists with all abused drugs. It is not limited to thebenzodiazepines. Normal subjects in double-blind studies do not generally“like” abused drugs, including stimulants, narcotics, and even alcohol. Peoplewho are not addicted to alcohol and other drugs do not like the feeling of beingintoxicated. Whether addicted people learn to like the intoxicated feeling orwhether they have some innate (perhaps genetically determined) differencethat explains this characteristic response to alcohol and controlled substancesremains an unanswered question of great importance to the prevention ofaddiction.When it comes to the outpatient treatment of anxiety in patients withactive addiction (e.g., current or recent abuse of alcohol or other drugs), the useof a controlled substance, including benzodiazepines, is generally contraindi-