Human beings are more complex and dynamic than an inflexible diagnostic definition. Mental health is about degrees on a spectrum rather than rigid categories, and so tests to measure disorders developed. (…) The idea is simple: many people (who might otherwise experience ‘good mental health’) under stress or at times of crisis behave in ways that look very much like the typical behaviours of those with specific personality disorders. Some become obsessive when faced with an unknown future. Others could become a tad paranoid after being victims of crime. Others avoid company when grieving a death.