Benzodiazepine Dependence

Benzodiazepine dependence or benzodiazepine addiction is when one has developed three or more of either tolerance, withdrawal symptoms, drug seeking behaviors, continued use despite harmful effects, and maladaptive pattern of substance use, according to the DSM-IV. In the case of benzodiazepine dependence however, the continued use seems to be associated with the avoidance of unpleasant withdrawal reaction rather than from the pleasurable effects of the drug. Benzodiazepine dependence develops with long term use, even at low therapeutic doses, even without the described dependence behavior.

Addiction, or what is sometimes referred to as psychological dependence, includes people misusing and/or craving the drug not to relieve withdrawal symptoms but to experience its euphoric and/or intoxicating effects. It is important to distinguish between addiction and drug abuse of benzodiazepines and normal physical dependence on benzodiazepines.The increased GABA_A inhibition caused by benzodiazepines is counteracted by the body's development of tolerance to the drug's effects; the development of tolerance occurs as a result of neuroadaptations, which result in decreased GABA inhibition and increased excitability of the glutamate system; these adaptations occur as a result of the body trying to overcome the central nervous system depressant effects of the drug to restore homeostasis. When benzodiazepines are stopped, these neuroadaptations are "unmasked" leading to hyper-excitability of the nervous system and the appearance of withdrawal symptoms.

Therapeutic dose dependence is the largest category of people dependent on benzodiazepines. These individuals typically do not escalate their doses to high levels or abuse their medication. Smaller groups include patients escalating their dosage to higher levels and drug misusers as well. It is unclear exactly how many people illicitly abuse benzodiazepines. Tolerance develops within days or weeks to the anticonvulsant, hypnotic muscle relaxant and after 4 months there is little evidence that benzodiazepines retain their anxiolytic properties. Some authors, however, disagree and feel that benzodiazepines retain their anxiolytic properties. Long-term benzodiazepine treatment may remain necessary in certain clinical conditions.

Dependence and misuse of benzodiazepines have been of concern since 2002. Based on findings in the US from the Treatment Episode Data Set (TEDS), an annual compilation of patient characteristics in substance abuse treatment facilities in the United States, admissions due to "primary tranquilizer" (including, but not limited to, benzodiazepine-type) drug use increased 79% from 1992 to 2002. Thus, the DAWN and TEDS data sets demonstrate clearly that the misuse of these sedative/hypnotics is on the rise, and cause for concern.

Numbers of benzodiazepine prescriptions have been declining, due primarily to concerns of dependence. In the short term, benzodiazepines can be effective drugs for acute anxiety or insomnia. With longer-term use, other therapies, both pharmacological and psychotherapeutic, become more effective. This is in part due to the greater effectiveness over time of other forms of therapy, and also due to the eventual development of pharmacological benzodiazepine tolerance.