Based in Washington, DC, the APA is a scientific and professional organization that represents psychology in the United States. With 150,000 members, APA is the largest association of psychologists worldwide.
The American Psychiatric Association is a medical specialty society with over 38,000 member physicians working to ensure humane care and effective treatment for all persons with mental disorder, including mental retardation and substance-related disorders.
Founded in 1988, the Association for Psychological Science (previously the American Psychological Society) is a nonprofit organization dedicated to the advancement of scientific psychology and its representation at the national and international level.
The Cognitive Science Society brings together researchers from many fields, including cognitive science, artificial intelligence, linguistics, anthropology, psychology, neuroscience, philosophy, and education, who seek to understand the nature of the human mind.
The mission of the NIMH is to transform the understanding and treatment of mental illnesses through basic and clinical research, paving the way for prevention, recovery and cure. Check out their Science News section.