The 'cuddle hormone' has a dark side: oxytocin amplifies gloomy memories in anxious adults

Oxytocin is popularly known as the 'cuddle' or 'bonding hormone'. A team led by Melissa Shemirani and Jennifer A. Bartz of McGill University in Montreal examined how the hormone affects childhood memories; the study was published in the journal Emotion, and the news site PsyPost reported on it on 16 October. 77 women and men visited the lab twice and, in a double-blind design and in varying order, received oxytocin once and a placebo once as a nasal spray. They then saw attachment-related words such as 'protect' or 'upset' and recalled memories of their mother; they described one positive and one negative memory aloud for a few minutes each.

Independent raters scored the transcripts. Among participants with high attachment anxiety – the fear of being rejected or abandoned by people close to them – memories under oxytocin were more negative and less positive than under placebo. In people with a more avoidant attachment style the hormone did not change the emotional tone; they disclosed less overall and were even more reserved on a follow-up questionnaire after oxytocin. The researchers see this as support for the so-called salience hypothesis: oxytocin amplifies social signals – pleasant and distressing alike – rather than simply producing warm feelings. Bartz described a similar pattern back in 2010 in a smaller study of 31 men in the journal PNAS: less anxiously attached men remembered their mothers as more caring under oxytocin, more anxiously attached men as less caring.

The study has limits: participants were relatively young and mostly White or Asian, and only memories of mothers were examined. Two text-analysis programs used in addition partly disagreed with the human raters – they found a significant effect mainly among participants with low anxiety, for whom oxytocin reduced the negative tone. The PsyPost report gives no details on funding. For possible therapeutic uses, the work urges caution: oxytocin is no cure-all and may intensify existing social fears, so any use would need careful supervision.