The relative global decline of the United States has become a frequent topic of debate in recent years. Proponents of the post-American view point to the 2008 global financial crisis, the prolonged recession that followed, and China's steady rise. Most are international relations experts who, viewing geopolitics through the lens of economic competitiveness, imagine the global order as a seesaw, in which one player's rise necessarily implies another's fall.

But the exclusive focus on economic indicators has prevented consideration of the geopolitical implications of a US domestic trend that is also frequently discussed, but by a separate group of experts: America's ever-increasing rate of severe mental disease (which has been very high for a long time).

The claim that the spread of severe mental illness has reached "epidemic" proportions has been heard so often that, like any commonplace, it has lost its ability to shock. But the repercussions for international politics of the disabling conditions diagnosed as manic-depressive illnesses (including major unipolar depression) and schizophrenia could not be more serious.

It has proved to be impossible to distinguish, either biologically or symptomatically, between different varieties of these conditions, which thus constitute a continuum - most likely of complexity, rather than severity. Indeed, the most common of these illnesses, unipolar depression, is the least complex in terms of its symptoms, but also the most lethal: 20 percent of depressed patients are estimated to commit suicide.

Manic-depressive illness and schizophrenia both are psychotic conditions, characterized by the patient's loss of control over his/her actions and thoughts, a recurrent state in which he/she cannot be considered an agent with free will. Obsessive suicidal thinking and paralyzing lack of motivation allow depressed patients to be classified as psychotic as well.