Section 1 describes the ways that psychologists define and classify abnormal behavior. By looking at deviance, adjustment, and psychological health, psychologists draw the line between normal and abnormal behavior. Psychologists use the precise diagnostic criteria of the DSM-IV to classify psychological disorders.

Section 2 identifies behavioral patterns that psychologists label anxiety disorders. These disorders, which are marked by excessive fear, caution, and attempts to avoid anxiety, include generalized anxiety disorder, phobic disorder, panic disorder, obsessive-compulsive disorder, and post-traumatic stress disorder. The symptoms and sources of each of these disorders are detailed in this section.

Section 3 discusses how anxiety and stress can bring about somatoform and dissociative disorders in some people. A somatoform disorder is characterized by physical symptoms brought about by stress. Examples of somatoform disorders include conversion disorders and hypochondriasis. Dissociative disorders involve a more significant breakdown of a person's normal conscious experience. This section describes dissociative amnesia, dissociative fugue, and dissociative identity disorder.

Section 4 is about schizophrenia and mood disorders. The section explains that schizophrenia is a serious psychological disorder and lists its symptoms. An interaction of environmental, genetic, and biochemical factors most likely cause schizophrenia. Mood disorders, such as depressive disorder, bipolar disorder, and SAD, involve disturbances in the experience and expression of emotions. This section includes several theories that try to explain mood disorders.