In my area, psych wards tend to have "single sex accommodation". In practice, that means that the men's bedrooms and hygiene facilities are on a different corridor of the ward from the women's bedrooms and hygiene facilities, and that there's a separate dayroom only women patients are meant to be able to use (in my experience, it doesn't get used much).
All the rest of the ward is shared space — main dayroom, dining area, any recreation or therapy facilities like the gym or occupational therapy areas, any outdoor spaces, and so on. Patients are generally encouraged not to spend much time in their bedrooms so in effect it's an entirely mixed-sex environment, with mobile, active patients who may be experiencing difficulty controlling their behaviour.