In dissociative amnesia, an individual develops a temporary inability to recall important personal information. The amnesia is more extensive than forgetfulness and is not caused by another medical or psychiatric condition (e.g., head trauma). The inability to recall information may take several forms. In localized amnesia, information is lost for a specific time period (e.g., a time associated with trauma). In selective amnesia, some information during a given time period is retained but other information is lost. In generalized amnesia, personal information is lost for the entire life span. In continuous amnesia, there is an inability to recall information from a single point in time to the present. In systematized amnesia, particular categories of information are lost to retrieval.

Dissociative amnesia is more common in people exposed to trauma, for example, exposure to battle or natural disaster.    

Somatization disorder is diagnosed when an individual has multiple medical complaints that are not the result of medical illness. The specific DSM-IV criteria are narrow and specific, requiring

• Pain in four different body sites or involving four different body functions;
• Two gastrointestinal symptoms (other than pain);
• One sexual symptom (other than pain); and
• One pseudoneurologic symptom (other than pain).

In addition, some symptoms must have begun before age 30 and persisted for several years. Individuals with somatization disorder often have a history of complex medical and surgical treatments that may actually lead to iatrogenic complications of treatment. Patients with somatoform disorder frequently have multiple physicians, make frequent office and hospital visits, and may seek disability because of their conviction that they are severely and chronically medically ill.    

Sleep disorders are illnesses related to alterations in the sleep-wake cycle (Table 9-7) and often have effects on mood, cognitive, somatic, and general performance. Table 9-8 outlines the DSM-IV classification of sleep disorders. Sleep disorders are categorized into primary and secondary sleep disorders. Primary sleep disorders are those disorders occurring as a direct result of disturbances in the sleep-wake cycle. They are divided into two categories: dyssomnias and parasomnias. Secondary sleep disorders are a consequence of other mental disorders (e.g., depression) due to general medical conditions (e.g., somatic pain) or substance use (e.g., caffeine).

Dyssomnias

Dyssomnias are five primary sleep disorders consisting of disturbances in initiating and maintaining sleep, feeling rested or refreshed after sleep, or sleeping excessively. Table 9-9 defines the DSM-IV determined key characteristics of each disorder.