Housing is a well-established determinant of health, influencing mental well-being through affordability, stability, and social engagement (Krieger and Higgins, Reference Krieger and Higgins2002; Bonnefoy, Reference Bonnefoy2007). While much research highlights the negative effects of poor housing, studies on positive housing models like cohousing are few but encouraging. Communal arrangements have been associated with reduced loneliness and improved well-being, particularly among older adults (Cramm and Nieboer, Reference Cramm and Nieboer2015; Glass, Reference Glass2013). Intergenerational cohousing promotes mutual support and a stronger sense of community (Markle et al. Reference Markle, Rodgers, Sanchez and Ballou2015; Williams, Reference Williams2005).

Cohousing, a model of community living that combines private dwellings with shared spaces and self-managed common facilities, originated in Denmark in the 1970s and has since spread globally (Vestbro and Horelli, Reference Vestbro and Horelli2012; Ruiu, Reference Ruiu2015). This growth is largely driven by a desire for stronger community ties and improved housing conditions (Jarvis, Reference Jarvis2019). Drawing on evolutionary theory, this paper explores cohousing’s potential to promote mental health by addressing modern mismatches in our living environments.

A recent review identified psychosocial benefits of cohousing, including increased social support, emotional security, and reduced isolation, particularly for seniors (Carerre et al. Reference Carerre, Pou and Larrea-Killinger2020). However, most findings come from small, cross-sectional studies, limiting causal conclusions. Still, these results align with broader evidence linking social support and community to improved mental and physical health outcomes (Leigh-Hunt et al. Reference Leigh-Hunt, Bagguley, Bash, Turner, Turnbull, Valtorta and Caan2017). Particularly for the older population, it has been shown that high social support and participation in social networks alleviates stress, reducing the rate of functional decline (Unger et al. Reference Unger, McAvay, Bruce, Berkman and Seeman1997) and mental health issues (Kawachi and Berkman, Reference Kawachi and Berkman2001).

An evolutionary perspective offers a compelling framework for understanding why cohousing might promote well-being, particularly as it can ‘bridge’ the gap between biological and social psychiatry (Swanepoel et al. Reference Swanepoel, Abed, Brar, St John-Smith and O’Connell2025). The theory of evolutionary mismatch posits that many modern health issues arise because our biology evolved under vastly different conditions than those we live in today (Abed and St John-Smith, Reference Abed and St John-Smith2022; Nesse and Williams Reference Nesse and Williams1994). For over 90% of human history, our ancestors lived in small, mobile hunter-gatherer groups, relying heavily on social cooperation for survival. These groups were typically composed of around 30–40 people, with low rates of close kinship but high interdependence (Marlowe, Reference Marlowe2005; Hill et al. Reference Hill, Walker, Božičević, Eder, Headland, Hewlett, Hurtado, Marlowe, Wiessner and Wood2011).

Modern housing environments – often marked by social isolation, limited contact with non-family members, and minimal communal interaction – contrast sharply with this ancestral norm. These mismatches may contribute to the rise in loneliness, depression, and other mental health issues observed in industrialized societies (Pontzer et al. Reference Pontzer, Wood and Raichlen2018). Shared living environments like cohousing may help counteract these trends by reinstating communal support and daily social interaction.

Mental well-being is deeply tied to our sense of community and belonging. Hunter-gatherer societies demonstrate strong social cohesion, with activities like storytelling, music, and dance reinforcing group bonds (Boehm, Reference Boehm1999; Wiessner, Reference Wiessner, Leacock and Lee1982) and report no subjective decline in well-being with age (Frackowiak et al. Reference Frackowiak, Chaudhary and Salali2020). These behaviors stimulate the endorphin system, reducing stress, and enhancing connection (Dunbar et al. Reference Dunbar, Kaskatis, MacDonald and Barra2016). In contrast, industrialized societies often lack these shared experiences, and social isolation has reached levels of global public health concern (World Health Organization, 2024).

Neuroscience supports these findings, loneliness activates brain regions associated with physical pain and increases stress hormones like cortisol (Eisenberger, Reference Eisenberger2012; Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010). For loneliness, the negative physical and mental health outcomes are well documented (Beutel et al. Reference Beutel, Klein, Brähler, Reiner, Jünger, Michal, Wiltink, Wild, Münzel, Lackner and Tibubos2017; Yanguas et al. Reference Yanguas, Pinazo-Henandis and Tarazona-Santabalbina2018). Conversely, community participation reduces stress and fosters well-being. Shared rituals, including secular ones, have been shown to boost trust, cooperation, and emotional health by increasing oxytocin and beta-endorphins (Beck et al. Reference Beck, Cesario, Yousefi and Enamoto2000; Fischer et al. Reference Fischer, Callander, Reddish and Bulbulia2013).

Participation in communal and spiritual practices has long provided structure, identity, and support. Although traditional religious involvement has declined in many societies, the mental health benefits of ritual and community remain significant. For instance, people engaged in religious or community rituals show lower stress levels and reduced risk of suicide (Duberstein et al. Reference Duberstein, Conwell, Conner, Eberly, Evinger and Caine2004).

Another major advantage of cohousing is the potential for shared childcare. In hunter-gatherer communities, child-rearing is a collective task, with infants cared for by a range of adults and older children (Kramer, Reference Kramer2010). This practice, known as alloparenting provides significant support to primary caregivers, reduces maternal stress, and enhances child development. In contrast, modern families often raise children in isolation, which can increase mental health risks for both children and parents particularly in single-parent households (Amato Reference Amato2000).

Cohousing communities that encourage shared caregiving and intergenerational playgroups recreate these ancestral dynamics. Young people also benefit from observing and participating in caregiving, developing nurturing skills early in life. Such environments promote social learning, reduce caregiver burden, and could help reduce the risk of post-partum depression (Chaudhary and Swanepoel, Reference Chaudhary and Swanepoel2023).

By aligning housing design with evolutionary insights, cohousing can be optimized to promote mental health. Ideal communities could approximate the scale and dynamics of hunter-gatherer groups, emphasizing shared spaces and collective routines. Importantly, these communities do not need to consist of relatives – cooperation with non-kin was equally vital in ancestral societies.

Features like communal kitchens, shared gardens, collective meals, and spaces for group activities can promote bonding and engagement. Activities that simulate ancestral experiences – singing, dancing, storytelling – could be integrated into community life.

While cohousing is not a panacea, it offers a promising response to the challenges posed by modern housing arrangements. It directly addresses social isolation, supports communal living, and mirrors some aspects of our evolutionary past that are missing from current lifestyles. Even when full cohousing is unfeasible, integrating community elements – like shared childcare, communal dining, or local rituals – can have meaningful impacts on mental health.

Further research is needed to rigorously assess the mental health benefits of cohousing. Well-designed longitudinal studies with larger samples and appropriate control groups are essential to establish causal relationships and identify which specific features of cohousing yield the greatest benefits. Such research could include long-term cohort studies comparing the mental health trajectories of cohousing residents with those living in conventional housing, or comparative studies examining which design elements and social practices are most strongly associated with positive outcomes. Nevertheless, both the evolutionary rationale and preliminary evidence indicate that key aspects of the cohousing model, especially those reflecting ancestral patterns of communal living, may offer substantial promise for enhancing mental well-being.