Chapter 2.3 Extinction of fear: From animal studies to clinical interventions

Abstract

Abstract Excessive fear and anxiety are hallmarks of a variety of disabling anxiety disorders that affect millions of people throughout the world. Hence, a greater understanding of the brain mechanisms involved in the inhibition of fear and anxiety is attracting increasing interest in the research community. In the laboratory, fear inhibition most often is studied through a procedure in which an organism previously trained to fear a cue is exposed to it in the absence of any aversive event. This procedure results in a decline in conditioned fear responses that is attributed to a process called fear extinction. In this chapter, we describe recent research on extinction of conditioned fear, focusing on observations in the laboratory that promise to inform clinical interventions for fear and anxiety disorders in humans. In particular, we will focus on research indicating that fear extinction in rodents and exposure therapy in humans are facilitated by a compound called d -cycloserine. We also will describe recent research suggesting that different mechanisms of extinction operate at different intervals between fear acquisition and extinction training.