Correction to: Neuropsychopharmacology (2012) 37, 1257–1266; doi:10.1038/npp.2011.313; published online 21 December 2011

To administer oxytocin or placebo the original drug Syntocin and the sodium chloride solution as placebo were dispensed in a nasal device DRUMO 3211, and, according to the manufacturer's instructions, for usage the dispensing volume was 0.10 ml.

The device was approved as appropriate for this purpose according to standard operating procedures of the Leiden University Medical Center pharmacy. The manufacturer of the DRUMO was a verified and certified manufacturer. The device was approved based on the data on the certificate of analysis. These procedures comply fully with GMP and GCP.

However, to test the dispensing volume the manufacturer used ethanol 100% instead of water as test substance without including this information in the certificate of analysis. As a result of this error, the dispensed volume of oxytocin in our study was lower than reported: 16 IU instead of 24 IU. The volume of 16 IU was established by the Leiden University Medical Center pharmacy in 2 × 10 trials according to pharmacopeia standard procedures. As this error occurred, although the procedures of the pharmacy were GMP compliant, we feel the urgent need to inform other investigators about this possible pitfall.

It should be noted that our findings remain the same, but the neural effects are based on a lower oxytocin volume.