Abstract
Mental health is sometimes understood as merely the absence of mental illness and sometimes more expansively as inclusive of a broader and more complete mental well-being. We present conceptual, empirical, and causal evidence for a distinction between the absence of mental illness and positive mental well-being. We discuss the implications for assessment, national tracking, research, policy, and mental healthcare. We argue for a greater clinical, policy, and public health attentiveness to positive mental well-being, to supplement work already being done on the treatment and prevention of mental illness.