If we are to believe the evidence from clinical trials there are many effective pharmacological and psychological treatments for mental illness. Epidemiological data, on the other hand, says otherwise.

Since the Second World War, rates of common mental illness (depression and anxiety) have been increasing in the industrialized nations, whereas rates of recovery from severe mental illness have not improved despite the availability of apparently effective therapies such as antipsychotic drugs.

At the population level, making the world more just and less unequal, while trying to figure out the toxic aspects of the urban environmental will probably help prevent a lot of psychosis.

Countries with the best-resourced medical services have the best outcomes for physical illness (it is better to have a heart attack in Washington or London than in rural Africa) whereas precisely the opposite is the case for mental illness (developing nations with limited psychiatric resources have better outcomes and lower suicide rates).

At the individual level, if we can identify the psychological mechanisms linking adverse environments to psychosis (and there has been a lot of progress with this despite minimal funding) we should be able to devise more effective interventions for those who are already ill.

Childhood trauma is not necessarily a prophecy of doom, because some children are resilient or because later experiences help to restore mental health.

The only way you can estimate environmental influences is by measuring them.