Gender differences in the prevalence and manifestations of depression probably result from a combination of biological, environmental, social, and other factors. Generalized anxiety disorder (GAD) is commonly comorbid with other anxiety disorders, substance abuse, and depression. Although sufferers relatively rarely seek medical advice, social anxiety is the most common anxiety disorder and the third most common psychiatric disorder in the USA. Comorbid depression, anxiety disorders, personality disorders, and substance abuse may complicate the diagnosis and management of obsessive-compulsive disorder (OCD). In addition to treating underlying medical conditions and avoiding substance abuse, the specific treatment of anxiety disorders is based on medication and psychotherapies. The principal medications used are antidepressants, benzodiazepines, and buspirone. The selective serotonin-reuptake inhibitors (SSRIs) are used widely to treat anxiety disorders, with or without comorbid depression, and have favorable side-effect profiles. Conversely, anxiety disorders often become comorbid with depression, and both conditions should be identified and managed.