By Alison Gee BBC World Business Report

Wall Street's stock brokers are as depressed as the prices of shares in dotcoms, according to research by a New York student in clinical psychology.

A study of male brokers in their 20s found they were three times more likely to suffer from clinical depression than men in general.

Cass has set-up a Wall Street consultancy

Alden Cass, a doctoral student at Nova Southeastern University in Florida, cultivated a circle of stockbrokers in New York to help him with his study.

The "New York City Stockbrokers and Stress" study found many showed manic symptoms - lack of sleep, delusions of grandeur, excessive risk taking, reckless spending and drug abuse.

Between the highs, Mr Cass found many brokers were deeply sad and anxious, and suffering from fatigue.

Would you trust them with your money?

In his survey - based on a so-called convenience sample rather than a random sample - 23% of brokers were clinically depressed compared with 7% of men as a whole.

But it is not just low share prices that bring psychological problems - when markets are riding high there is even more pressure for brokers to make large sums of money.

It seemed their inability to control the markets can make them depressed and this macho environment, where they are not encouraged to talk about their feelings, the result is a sense of isolation.

However another study found that brokers in the southern state of Florida were less likely to be depressed - partly because of the climate and the different environment.

Investor concern

Mr Cass believes the findings should interest anyone who has money invested in the financial markets.

When brokers feel down, he says, the number of calls they make to potential investors can fall by as much as 50%, which in turn can mean there is less new money available to help push up share prices.

The mental health of people in the financial world has also caught the interest of influential financial organisations in the US, such as the Federal Reserve Bank of New York and the Securities Industry Association, which are keen to highlight the problem and warn brokers how to recognise the warning signs

Mr Cass has become a partner of Schachter-Cass Associates and hopes to cash-in on the research by advising investment banks and brokers.