In 2016 Belgian researchers released their previously unpublished studies:
“Is there a file drawer problem in intranasal oxytocin research?
We submitted several studies yielding null-findings to different journals but they were rejected time and time again.
The aggregated effect size was not reliably different from zero [including all of the researchers’ previously unpublished intranasal oxytocin studies].”
“By publishing these results, Lane et al. have ensured that future meta-analysts will be able to include the full dataset in their calculations.”
http://blogs.discovermagazine.com/neuroskeptic/2016/03/17/open-the-file-drawer/ “Psychologists Throw Open the File Drawer”
See Testing the null hypothesis of oxytocin’s effects in humans for more on the topic.