far proved complex and elusive to understand even one of the most heritable disorders schizophrenia appears linked to small variations in more than a hundred genetic regions recently though a genetic variant has been identified that seems to ignite excessive pruning of synapses in a key brain area in people with schizophreniadepression has been one of the toughest to figure out partly because it affects different people in different waysyou might have an 18yearold woman who is doing selfcutting and shes got depression dr sullivan said and a 64yearold woman with hypertension and type 2 diabetes and shes got depressionbecause postpartum depression afflicts a narrower group of women who have recently given birth it may be easier to study dr sullivan said he said he and some colleagues had recently conducted a study that suggested postpartum depression was more heritable than general depression dr addington said there might be genes that specifically influence a womans sensitivity to hormonal fluctuations in pregnancybut david goldstein director of columbia universitys institute for genomic medicine who is not involved in the project said another possibility was that postpartum depressions links to hormonal fluctuations in addition to emotional and other stresses that can accompany having children might indicate it was less likely to be genetiche said he had no objection to the projects goal but its possible that you can collect information from tens of thousands of individuals and not find anythingdr kenneth s kendler director of psychiatric genetics research at virginia commonwealth university who is not involved in the project said some evidence suggested that genes involved in postpartum depression differed somewhat from those in general depression ideally the project will find fewer gene variants involved and they are bigger in effect size he saidits a reasonable bet dr kendler added but its not a slam dunk