The conversation on mental health has opened up once again this week following the tragic suicide of Robin Williams after a lengthy battle with depression.

Williams' death coincides with Deputy Prime Minister Nick Clegg's recent comments on the need for greater investment into mental health research.

Announcing that the Lib Dem manifesto will pledge to increase spending in the sector by £50 million by 2020, Clegg insisted that a breakthrough "comparable to penicillin" is needed.

His comments have been praised by campaigners, though some have been sceptical about the timing of his remarks in the run up to the 2015 election. Those working to reduce the stigma associated with mental health in the Church, however, have expressed a hope that Clegg's comments point to a transformation in our cultural approach to mental illness.

Will van der Hart, pastoral chaplain at HTB church in London and director of Mind and Soul, a Christian charity working to reduce stigmatisation of mental health both within the Church and wider society, himself suffered from post-traumatic anxiety following the 7/7 bombings, during which he opened up his church to police and security personnel.

"Nick Clegg said something we've known for a long time, which is that mental health spending has been reduced under the coalition government. There have been attempts to make sure that services remain the same or similar in terms of provision, but they've lacked any investment and innovation in treatment and research," van der Hart explains.

"Psychological medication is not a huge area of interest for companies, it's not a great money making area, and therefore ultimately there's a financial bottom line, and a lack of interest.

"If you look at cancer as a health issue, there isn't a stigma, there's a lot of public empathy and therefore most of the money invested from a charitable perspective goes to research on cancer. Millions is poured into cancer research, and that's brilliant and we absolutely endorse that, but mental health charities aren't able to do that in the same way – we don't have the funds, we can't generate finance for research, and we really need to see a significant investment.

"The newspapers I've read reflected on the huge social cost of mental health, which is far greater than many of the most significant and sinister physical diseases, and yet the investment is far less than those."

Mind and Soul is working to "capture the public imagination" and eliminate the idea that mental health is something only supposedly "weak" people struggle with.

The Church has a long way to go in this, van der Hart says.

"Different denominations have different attitudes, and some are further down the track than others, but I've still found in some congregations and traditions that there's a very simplistic and spiritualised view of mental health problems," he says.

"Others have a more psychologically attuned view, but have lost sight of the power of God's supernatural presence – there's a danger of the Church over spiritualising and not finding the best possible psychological treatment, but then there's also the danger of focusing on psychology and not seeing the benefits of the gospel which is good news for everyone, regardless of mental health. So it's really a balance."

Van der Hart adds that it's important to "stop stigmatising and ostracising people we don't understand, and start showing love and respect to those who are suffering."

"It's like the story of the good Samaritan – there are loads of people in the church who are broken, bruised and bloodied on the floor, and people are crossing over to the other side and thinking – that's not an area I'm willing to engage with or offer support to. So our reducing the stigma work goes on."

Interestingly, in the wake of Robin Williams' death, Christians on Twitter have been opening up the conversation further about walking through depression and other mental illnesses while holding onto a belief in God, using the hashtag #FaithintheFog.

Van der Hart gives examples of struggling Christians being told to have faith, flee from fear and to silence the demon voices in their heads, which he says can be very dehabilitating. Similar stories have also been shared on Twitter:

Cathy Wield, a Christian doctor who has depression, says people at a loss for what to say usually end up saying something unhelpful, which has made her feel incredible isolated in the past.

"I'd like to hear 'I'm really sorry, I'll be there for you, when can we have coffee?' rather than 'Oh it's alright, I'll pray for you and it'll be gone,'" she explains.

"There's a tendency for people to want to pray for healing for things, but often it's a sticking plaster prayer, rather than a deep healing. And I think to say 'I'll pray for you' means next to nothing – you may or may not pray for them. And what people [who suffer with mental illness] want is real understanding and comfort, and they want other people to be real. Depression is incredibly common, but there's a long way to go on the road to getting there."

Wield and her husband run workshops to educate churches about depression and its causes, as well as the theology behind it. "We want to take the myth out of 'you must be joyful all the time'," she says.

"Often verses are quoted out of context – the Bible says Jesus was a man of sorrow, not a man of hilarity and laughter, though I'm sure he did laugh and had those aspects to his character. But the emphasis is on his sorrow; he does understand and he is with us. We also focus on the fatherhood of God – that we are his children and he accepts us unconditionally."

Van der Hart says the journey is really just beginning for those looking to see physical and mental health put on the same platform.

"The key thing is being willing to work over a long period – people have often had a propensity towards mental illness since childhood or adolescence, and it's a living recovery and a lifelong journey," he says.

"It doesn't happen in a moment for the vast majority, and an acceptance of the journey and a willingness to travel over the long haul is essential. We have to look at emotional health as a continuum, rather than a blip on the screen of life."

Mind and Soul are launching a free mental health resource pack for churches across the UK, with suggestions for better practices, policies and outlooks. It also includes sermons, illustrations and guides on prominent mental health and theological outlooks. For more details, check out the website here.