After thousands of clinical trials, the efficacy of psychotropic drugs in the treatment of psychiatric disorders has become well established. However, the very success of these drugs has meant that many patients with chronic illnesses will receive them for a significant part of their lifetime. Side effects and other adverse reactions are an unfortunate but unavoidable component of successful pharmacotherapy. In- deed, the main emphasis in new drug development is often on the search for compounds that have fewer side effects, although no one has as yet found an effective drug without them. Therefore, it is important for clinicians to be aware of side effect reaction profiles, because they are often a major determining factor in the choice of therapy. After more than three decades of major breakthroughs in the development of psychotropic drugs, reactions to these medications are still frequently reported in the current liter- ature, and information about well-known reactions is con- stantly refined. This book is an attempt to systematically collect and organize this large body of data and present it in an easy-to-use form. All chapters follow the same reaction- oriented logic, and each important reaction is discussed using the same consistent subdivisions. The more clinically impor- tant reactions appear in the body of each chapter; the more unusual or rarely reported reactions are briefly characterized in the miscellaneous section at the end of each chapter.