[Animal models of 'anxiety']

Many animal models of anxiety have been reported; for example, Geller-type or Vogel-type anticonflict tests and ethologically based tests without punishment such as a light/dark test, a hole-board test, a social interaction test, an elevated plus-maze test and so on. These models were pharmacologically validated by the evidence that clinically useful anxiolytic benzodiazepines were active, but activities of serotonergic anxiolytics in these models were inconsistent. These models might measure a mixture of several types of anxiety. Many disorders of anxiety are classified in the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) and several disorders can not be treated with benzodiazepines very well. Animal models to evaluate the drugs for the benzodiazepine-untreatable disorders are needed. Graeff et al. performed studies to measure inhibitory avoidance latency from an enclosed arm to open arms and escape latency from the open arms to the enclosed arm as parameters of conditioned and unconditioned fears, respectively, in the elevated T-maze in rats. The latter was suggested for use in the evaluation of drugs efficacious on a panic disorder. A marble burying test as an animal model for an obsessive-compulsive disorder was also reported. However, establishment of the models for these disorders remains for future investigations.