The power of touch can ease depression and anxiety

The idea that touch, when it's wanted, can boost both physical and mental health is well-established. But the wealth of studies in this area has produced such an array of findings that it can be tricky to draw clear conclusions about just how beneficial touch can be, and which types of touch are most effective.

In a new report, published recently in Nature Human Behaviour, Julian Packheiser and colleagues make a major attempt to address this. The team conducted a systematic review and meta-analysis of more than 217 touch studies on a total of almost 13,000 people, mostly involving skin-to-skin 'kangaroo care' interventions for babies, and massage sessions for adults. The many notable results from their analysis could be used to improve touch interventions — and highlight areas where more research is needed.

The paper itself is massive, and offers many subtle insights (so definitely dip in and have a read). For your convenience, we've summarised the main beats:

Scale of the impact

Overall, touch interventions had the same, medium-sized effect on both adults and newborns.

For newborns, there wasn't enough data to explore mental health effects. But of the physical health outcomes that were measured, only two — digestion and heart rate — were unaffected by touch. With all the others — levels of the stress hormone cortisol, liver enzymes, respiration, temperature regulation, and weight gain — touch interventions had medium-to-large effects.

For adults, touch improved various measures of both physical and mental wellbeing. However, it was especially effective at reducing pain, feelings of depression, and anxiety.

Who — or what — administers the touch

Babies enjoyed bigger benefits when it came from the parent (usually the mother in these studies) than from a health professional. For adults, on the other hand, there were no differences in the effects of touches administered by someone they knew or a health professional.

Whether adult participants were touched by another human or an object, such as a robotic massager, the physiological outcomes were similar. However, the analysis revealed that for mental health, specifically, there were bigger benefits to being touched by another person.

In sickness and in health

The analysis revealed similar levels of mental and physical health benefits across the various patient groups, suggesting that touch is broadly effective. The only group that stood out as benefiting even more than others was adults with neurological disorders — though the reason for this was not explored.

The analysis also showed, importantly, that though there were even bigger mental health benefits for patient groups, people without any serious health problems benefited broadly from touch interventions, too. "These data are critical as most previous meta-analytic research has focused on individuals diagnosed with clinical disorders," the team writes.  

Sex and age

There were no sex differences in the benefits of touch for newborns, for which the studies featured equal numbers of boys and girls, However, in adults, the results suggested larger mental and physical health benefits for women than men.

Looking at data from just those aged 18 or older, there was no consistent link between age and the overall health benefits of the touch interventions, though when the oldest participants were compared with young people, the results suggested that they enjoyed bigger improvements in positive emotions and blood pressure, specifically.

Physical locations

Kangaroo care generally involves holding a baby wearing just a nappy against the adult's skin. This made for relatively little variation between studies in where the babies were touched. For the adult groups, there were some differences, and the team found that touch to the head was more effective at improving physical and mental health scores than touch to the arm or the torso. "Thus, head touch such as a face or scalp massage could be especially beneficial," they write.

Whether the touch happened at home or in a clinic or other professional setting had no impact on the benefits.

More touch isn't always better

The team found a link between more touch sessions for adults (the median was four) and bigger improvements in depression, anxiety, and pain. However, there were no additional health benefits to sessions that were longer than the median of 20 minutes (in fact, long sessions had some negative implications). For newborns, there was no link between the duration of the touch and weight gain.

Non-human animals also feel the benefits

The researchers also considered 19 studies of touch on a total of just under 1,000 animals. Most of these studies were on rats and mice, though others featured macaques, cats, lambs, and even coral reef fish. The touch interventions were generally done by people (rather than objects) and involved stroking or tickling. The analysis produced "strong evidence" that these touch interventions had positive physical and mental-health-like effects in animals, too, by reducing levels of stress hormones, for example.

The future

The team hopes that these results will inform future research in the area — for example, on whether massage delivered by robots with more human-like skin, for example, might be as effective as massage from another person, or whether the hints of sex differences in impacts on adults are real, or merely an artefact of relatively sparse data on men.

For now, the findings do suggest that touch can improve a variety of health outcomes, and given current levels of anxiety, depression, and pain, the finding that it's especially effective for these conditions is an important one, and as the authors conclude, one that can be "employed across the population to preserve and improve our health."

Read the paper in full:

Packheiser, J., Hartmann, H., Fredriksen, K. et al. A systematic review and multivariate meta-analysis of the physical and mental health benefits of touch interventions. Nat Hum Behav (2024). https://doi.org/10.1038/s41562-024-01841-8