The idea that psychological disorders are independent of underlying mental illness has been widely accepted for decades.
In this article, we provide a systematic review and meta-analysis to show that this assumption is not supported.
We show that the relationship between psychological disorders and mortality is highly variable, but the underlying mechanism is not identified.
Rather, it is clear that the link is due to the effect of the disorder on cognition and social function.
Our results show that psychosocial stressors are the most important risk factor for the onset of a mental disorder, but there is no evidence that they are the main driver of psychiatric morbidities and mortality.
We also show that psychopathological disorders are more common in people who have a history of psychiatric hospitalisation.