Conventional psychiatry has emphasized the genetic roots of psychosis based on the claim that twin and other studies show that schizophrenia is 80% heritable, which means that 80% of the cause is genetic.

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.

There is almost no evidence that diagnoses such as 'schizophrenia' and 'bipolar disorder' correspond to discrete entities ('natural kinds' in the language of philosophy).

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

There are many kinds of adult adversities that can provoke severe psychological distress, including debt and unemployment, dysfunctional marital relationships and occupational stress. The reality is that the social causes of mental ill-health are all around us.

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.

My interest in the psychological roots of psychosis has both personal (my brother Andrew committed suicide) and professional origins (I was trained in a behaviorist approach to psychology which - whatever its limitations - at least taught me to see human behavior in its social context).