How can adult mental health be managed in a health care setting in the US and the UK?

Though the United States and United Kingdom overlap in many areas of policy, they differ dramatically in their approaches to adult healthcare. The UK implements socialized medicine, which means that access to healthcare is universally available and paid for by the state through progressive taxes on income and capital.
On the other hand, the US healthcare system is privatized. Citizens do not have a right to healthcare, not to mention affordable healthcare. Healthcare and insurance providers in the US tend to prioritize their financial interests over any moral imperative to administer healthcare to those who can't afford it. As a result, at least 50 million Americans are presently without any coverage. Another consequence is that the US healthcare system systematically privileges white, affluent demographics over poorer minority demographics, exacerbating an already difficult wealth inequality epidemic. Recent plans, such as the Affordable Care Act (discontinued under the Trump administration) seek a more socialized approach to healthcare by forcing providers and insurers to act in citizens' best interests.