The largest private nonprofit provider of mental health, substance use, special education, developmental disability, and social services in the nation. The nation's largest private, nonprofit provider of mental health, special education, substance use, developmental disability, and social services. ALLIANCE, INC., A SUBSIDIARY OF SHEPPARD PRATT, A NOT-FOR-PROFIT BEHAVIORAL HEALTH SYSTEM, IS DEDICATED TO IMPROVING THE QUALITY OF LIFE OF INDIVIDUALS AND FAMILIES BY COMPASSIONATELY SERVING THEIR MENTAL HEALTH, ADDICTION, SPECIAL EDUCATION, AND COMMUNITY SUPPORT NEEDS.