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.

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

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

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).

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 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.

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