Sheppard Pratt | 24,290 followers on LinkedIn. Sheppard Pratt is the largest private, nonprofit provider of mental health, substance use, developmental disability, special education, and social services in the country. A nationwide resource, Sheppard Pratt provides services across a comprehensive continuum of care, spanning both hospital- and community-based resources. Since its founding in 1853, Sheppard Pratt has been innovating the field through research, best practice implementation, and a focus on improving the quality of mental health care on a global level.