The subtle relationship between depression, gender and life events (such as motherhood) creates a global challenge to the United Nations' sustainable development goals. ^{Reference Caan1} Du Preez and colleagues make a fascinating contribution to the epidemiology of postnatal depression. ^{Reference Du Preez, Conroy, Pawlby, Moran and Pariante2} However, as someone interested in family and household effects on mental health ^{Reference Caan3} I wonder if they missed a key ‘protective’ aspect of having ‘higher own ethnic density’ in a mother's locality? ^{Reference Du Preez, Conroy, Pawlby, Moran and Pariante2} My own observation on British White mothers in a mixed community with marked deprivation and high levels of postnatal depression ^{Reference Northrop, Pittam and Caan4} was that having close relatives (like the baby's grandmother) living nearby made for a healthier new mum. Close relatives tend to belong to the same ethnic group, as do those ‘good neighbours’ who maintain frequent visits. The local risk of developing depression seems to be influenced by very short-range social networks of close relatives and neighbours. ^{Reference Christakis and Fowler5} In that poor community with so much postnatal depression, ^{Reference Northrop, Pittam and Caan4} it transpired that many mothers had no relatives in the area and did not see any friends among their neighbours.