In recent years we have seen a sea-change in public attitudes towards people suffering from mental ill health.

Increasingly, mental health problems such as depression are recognised as medical issues and treated as such.

This change has not come easily and it is clear that we still have a long way to go. Charities such as the Scottish Association for mental health have been working for decades to highlight the stigma people suffering from mental ill health face.

The scale of the challenge that addressing issues of mental ill health presents to our NHS is enormous. Recent research suggests that almost one in three GP appointments in Scotland relates to mental ill health. It is estimated that one in four of us will experience mental ill health in our lifetimes. Some 2.3 million people with a mental health condition are out of work and research has identified mental ill health as the primary reason for claiming health related benefits.

Despite this, mental health has for too long been the Cinderella service of our NHS. An increase in awareness of the costs associated with mental ill health has, by and large, not been matched by increased investment in Scottish mental health services.

At the Liberal Democrat conference in Glasgow, Deputy Prime Minister Nick Clegg was the first party leader I can remember to have put improving mental health services front and centre of his keynote address.

Boosting mental health services in England will be one of our key manifesto priorities going into the General Election, by which time new treatment targets will have come into force and new money will have gone to crucial research.

The decision to introduce treatment targets for the first time in England has been welcomed by campaigners, and corrects the decision of the Labour government to leave out mental health when maximum waiting time targets were first introduced. This created an institutional bias against mental health that has persisted for too long.

In Scotland, we already have some treatment targets in place. But the challenges we face are no less than those south of the border. The most recent data shows that almost half of Scotland's NHS boards missed treatment targets for helping vulnerable young people suffering with mental ill health. We need urgent action to turn this situation around.

A vital first step is for Scottish ministers to match the work that LibDem ministers in government have done to put mental and physical treatments on an equal footing in law. The action taken in England will help guarantee parity of esteem between mental and physical health and ensure that the NHS has a responsibility to consider mental health treatments in the same way as those for any other illnesses.

A second step is to ensure that the Scottish Government budget includes adequate provision for mental health services. This is something that Willie Rennie, the leader of the Scottish LibDems, raised with Finance Secretary John Swinney after the presentation of the first draft of the 2015/16 budget at Holyrood. Mr Swinney undertook to work with us to ensure that due consideration is given to mental health when spending decisions are being taken. These words now need to translate into action.

A third step is to ensure that the Mental Health Bill the Scottish Parliament is considering at present includes robust measures to improve services. The consultative stage of the Bill will continue until February and MSPs on the Health Committee are continuing to take evidence.

Anyone who feels strongly about this issue must take the opportunity to ensure that their views are represented at Holyrood as this legislation moves forward.

The problems we are seeing in our mental health services are too important to be brushed under the carpet. Boosting services and increasing investment will not come cheap.

But we cannot afford not to act.