A 2010 review found few studies of medications for treating PPD noting small sample sizes and generally weak evidence. Some evidence suggests that mothers with PPD will respond similarly to people with major depressive disorder. There is evidence which suggests that selective serotonin reuptake inhibitors (SSRIs) are effective treatment for PPD. The first-line anti-depressant medication of choice is sertraline, an SSRI, as very little of it passes into the breast milk and, as a result, to the child. However, a recent study has found that adding sertraline to psychotherapy does not appear to confer any additional benefit. Therefore, it is not completely clear which antidepressants, if any, are most effective for treatment of PPD, and for whom antidepressants would be a better option than non-pharmacotherapy.