The UK's drug laws are preventing scientists from carrying out vital research to unlock our understanding of the brain and find new treatments for conditions such as depression and Parkinson's disease, according to Professor David Nutt, a leading neuroscientist and former government drug adviser.

"Things are actually getting worse," said Nutt, referring to the restrictions placed on research. "It's the dark ages beginning to descend in this field. [The UK] led the world in discovering the constituents of cannabis – about 100 individual substances, all of which can have therapeutic value – and we've exploited virtually none of it because it's too difficult."

On Monday, Prof Nutt was awarded the 2013 John Maddox Prize, in recognition of his courage in "promoting science and evidence on a matter of public interest, despite facing difficulty and hostility in doing so." In their citation, the judges said they wanted to recognise Prof Nutt's impact on the evidence-based classification of drugs, in the UK and elsewhere in the world.

In 2009, Prof Nutt was sacked by the then health secretary, Alan Johnson, from his post as chair of the government's Advisory Council on the Misuse of Drugs for publicly stating that alcohol and tobacco were more harmful than LSD, ecstasy and cannabis. Despite his dismissal, his forthright views on drugs have rarely been out of the headlines and he has continued to campaign for a more rational government policy on drugs that takes into account the actual harms caused by them.

Nutt told the Guardian that legislation had been "very much more detrimental to research than people had imagined". For example, the authorities can impose "temporary banning orders" on new street drugs, and these can inadvertently prevent scientists from doing anything to find out what, if any, therapeutic uses the substances could have.

He has warned before that the UK's drug regulations would have adverse impacts on scientific research, given the hurdles and red tape that scientists face if they want to work on anything that is banned. Researchers who want to experiment on illegal drugs, which come under the schedule 1 list of the Misuse of Drugs Regulations 2001, have to apply for a licence from the Home Office. This can take a year and costs thousands of pounds. Researchers are also required to have secure storage facilities and are subject to random inspections by police.

More than 15 years ago, scientists disovered that MDMA, the active ingredient in ecstasy, could be helpful in controlling some of the problems suffered by Parkinson's disease patients who found their movements became less coordinated after years on conventional drug treatments. "But it's never been taken forward as a therapy because it's illegal," said Prof Nutt. "The costs of working in this field mean that pharma companies won't do it."

In the US, scientists have also found that MDMA can damp down the negative emotions associated with trauma, allowing patients to make more effective use of therapy. Even if trials of the drug could be carried out in the UK, however, no doctor would be allowed to prescribe the drug.

Clinical trials of psychedelic substances such as LSD in the 1950s and 1960s showed that they could be used to treat alcohol addiction. But, because LSD was subsequently banned around the world, there have been no studies using modern imaging techniques such as magnetic resonance imaging (MRI) to examine how these drugs affect the brain.

"The science of consciousness, the science of serotonin, the science of empathy, those basic sciences are limited by the current rules to a point where people don't even consider [it]," said Prof Nutt. "Clinically – pain, Parkinson's disease, depression – are three areas where progress has been stunted or blocked. The regulations make it so difficult that most people don't have the strength of will. [The research] doesn't happen at all."

He added that many of the problems were down to "gesture politics" that led to the authorities routinely putting recreational drugs into schedule 1, the highest category of ban. "There's another rule made 50 years ago that has never been reconsidered, which is that schedule 1 drugs need special licences," he said. "There's no reason for that. Why is it that I can work with heroin every day of the week but I have to get a special licence to work with cannabis? Does that make any sense? Heroin is much more harmful. These are archaic, arbitrary regulations that are stifling research. The government has become much more bureaucratic in the last couple of years about this and that's made a lot of researchers give up."

Nutt said that a potential solution would be to take the control of drugs out of the Home Office. "Part of the problem in this country, unlike most countries in the world, we see drugs simply as an issue of law and order," he said. "Therefore, if you ask police what to do about drugs they say, 'make them illegal and lock them up'. If [drugs] were in health, we could have a much more rational approach."

Awarding this year's John Maddox Prize, professor Colin Blakemore, a neuroscientist at the University of Oxford and one of the judges, said that working "in circumstances that would have humiliated and silenced most people, [Prof Nutt] continued to affirm the importance of evidence in understanding the harms of drugs and in developing drug policy. He took personal risk to his reputation in the name of sound science and in defending the right of researchers to present scientific opinion publicly. Policy makers are, of course, not compelled to follow scientific advice, but they are accountable to the public and to their own advisers if they choose not to do so. We need people like David Nutt to assert the independence of scientific advice and to inform the public when government policy departs from that advice."

Sir Paul Nurse, president of the Royal Society, said that Prof Nutt was "a bold scientist who will inspire others to keep evidence at the centre of public and policy debates about science."

The John Maddox Prize is now in its second year, and a joint initiative of science journal Nature, the Kohn Foundation and the charity Sense About Science. Last year's winners were psychiatrist professor Simon Wessely and Shi-min Fang.