An investigation has been launched into the high cost of city mental health services.

Brighton and Hove City Council and the NHS primary care trust will spend £30 million this year looking after patients and sufferers.

The bill is £2 million higher than similar towns and cities in Britain and councillors and health bosses are determined to find out why.

People living in Brighton and Hove pay £137 compared with an average cost of £121 nationally and the latest report to the joint commissioning board warns the service could slip over budget.

Councillors have approved a new commissioning strategy for working age mental health services and the document will go out for public consultation.

Councillor Anne Meadows, deputy chairman of the commissioning board and the main representative for the city council, said: "We have to find out if it is the cost of services that is too high, if it is more people accessing the services or if we have more services than other areas."

An estimated total of 37,000 adults in the city aged 16 to 65 suffer from mental health problems. This includes 28,616 people with neurotic disorders such as anxiety, depression and 2,092 patients suffering phobias.

There are 7,546 sufferers of personality disorders, 3,391 with obsessive compulsive disorder and 1,375 with paranoia.

A total of 1,290 people suffer schizophrenia and up to 3,720 have manic depression.

An average of 38 deaths are recorded as suicide or undetermined injury each year in the city. This is higher than the national rate and contributes to a national total of 4,500 suicides every 12 months.

While suicide is the most common cause of death for men under 35 across the country, in Brighton and Hove accidental overdoses kill more people of that age.

The cost of providing primary care counselling has reached £318,000 this year with £82,500 spent on specialist care from voluntary services. A total of £11 million is spent on community care, including rehabilitation, residential care and voluntary sector advice.

A new primary care mental health service will be launched in April next year to help people with anxiety, depression and other common problems. This will cost £350,000 for the primary care trust but practitioners hope it will reduce costs by treating people earlier.