Discovery of novel anxiolytic agents--the trials and tribulations of pre-clinical models of anxiety.

Anxiety disorders are the most common class of mental disorders present in the general population with an estimated lifetime prevalence of any anxiety disorder being approximately 15%, while the 12-month prevalence is more than 10%. They are classified into simple phobias, social phobias, obsessive-compulsive disorder (OCD) and panic attacks. Anxiety disorders are more prevalent in females than males and respond to pharmacological and non-pharmacological (behavioral) treatments. Anxiety disorders are complex with genetic and environmental factors interacting to produce the final psychopathology. There are many tests used to detect behaviors that indicate heightened anxiety in rodents however there are few pathological models of anxiety in rodents. Most compound testing is performed on naive, non-pathologically anxious, male animals which is a potential limitation to current strategies since these animals do not reflect the anxious patient. This article briefly describes some of the most common anxiety tests used in rodent research and concludes with a short perspective on areas the field could concentrate on to improve the understanding and successful translation of novel targets into new therapies in the clinic.