A report by the think-tank revealed NHS mental health trusts in England received a 2.5% increase in funding in 2016-17 compared to more than 6% for acute and specialist trusts.
The King’s Fund said the government prioritised A&E services despite a pledge in 2013 to achieve “parity of esteem” between physical and mental health.
The report said the number of mental health nurses had fallen 13% since 2009, and that 10% of all posts in specialist mental health services stand vacant.
An analysis of Care Quality Commission inspection reports showed that patient safety was being jeopardised in more than half of the 54 mental health trusts because of problems with staffing, increasing the risk of suicide and self-harm on inpatient wards.
Report author Helen Gilburt said: “Unless funding grows more quickly, mental health providers may end up implementing improvements to some services at the expense of others.
“Despite the commitment of national leaders, the funding gap between mental health and acute NHS services is continuing to widen, while growing staff shortages are affecting the quality and safety of care.
“As long as this is the case, the government’s mission to tackle the burning injustices faced by people with mental health problems will remain out of reach.”
Mental health campaigners called on the government to increase investment and to effectively implement the Five Year Forward View for Mental Health strategy published in 2016.
Saffron Cordery, director of policy and strategy and deputy chief executive of NHS Providers, said: “While we welcome extra funding, budgets in mental health services are more stretched than ever.
“Services face rapidly rising demand, with over 70% of mental health leaders telling us last year they expect demand to rise further.
“More must be done to ensure that funding earmarked for mental health services, and to implement the five year forward view, reaches frontline providers.”
Sean Duggan, chief executive of the Mental Health Network, said: “The government has pledged to put mental health on a par with physical health but this needs to be reflected in investment and the continued progress of the Five Year Forward View for Mental Health.
“Securing a sustainable mental health workforce fit for the 21st century is a crucial part of this.
“Getting mental health services right will relieve pressure on other parts of the health system and we would urge the government to deliver on its promises and ensure mental health gets the equal status it deserves.”
