No matter where you are, depression responds to the same treatment.

Depression has existed as long as mankind itself, and certainly well before psychiatry, antidepressant medication, or the nation of America itself came into being.

There seems little doubt in my mind that depression, in particular at the severe end of the experience of this condition, is as real a disorder as diabetes is at the severe end of blood glucose levels.

In my mind, depression is, like all non-communicable diseases, a physiologically expressed condition which is profoundly influenced by our social and cultural environments. Depression is a global crisis not only because it is common and universal, but because the vast majority of affected people suffer in silence or receive inappropriate care.

I think the government must recognise that the wounds of conflict are even more grievous on the mind than the body, and indeed may even serve to fuel further conflict. Where conflict cannot be avoided, provision of adequate psychosocial services to prevent the adverse mental health consequences should take priority.

I learned so much in Zimbabwe, in particular about the need for humility in our ambition to extend mental health care in countries where there were very few psychiatrists and where the local culture harboured very different views about mental illness and healing. These experiences have profoundly influenced my thinking.