A profoundly depressed person may well not be capable of suicide. This could account for the increased longevity of modern Western man, rather than public health measures and medicine alone. More modern humans than in the past are simply too depressed to commit suicide. But every so often there is a cycle of collective improvement in the mass psyche. Perhaps it is occasioned by a slight reduction in the mass consumerism and endless striving after wealth and status. More individuals become less depressed and this improvement in the mass psyche is generally manifested as a mass suicide-homicide movement, perhaps a local conflict or major war.