One of the paradoxes of the modern age is plummeting global poverty matched almost perfectly with rising clinical depression. Like never before we can defeat diseases, survive childbirth, elude predators, avoid war, and enjoy leisure, yet never before we been so unhappy. How can this be?
At medical school we learnt very few certainties. Everything was a possibility, a probability, a risk, a trend, a likelihood. There were many rules of thumb, but very few rules. Yet amongst all the qualified circumspection, there was one iron-clad law: The human brain grows no new neurons. All the neurons we would ever have were present at birth, and from there it was all rapidly downhill for our neuron tally.
Scientists have long observed an association between depression and heart disease. Depressed adults have a 66% greater risk of developing coronary artery disease. These patients are also more likely to progress to serious outcomes such as a heart attack – at least a quarter of cardiac patients suffer with depression.