Katharine Welby-Roberts writes and speaks about issues around mental and emotional health and how the church can better serve people with long-term suffering. Her first book, 'I Thought There Would be Cake', is a raw, personal and often funny exploration of how to navigate depression and anxiety and allow yourself to be loved.

Katharine is a wife, a mother and a dog-owner. Jo Swinney, a fellow survivor of depression, spent an afternoon with her by the fire, putting the world to rights.

JS Did you first hit mental health issues as a child? In your book you write about having a group of school friends inexplicably turn on you. Was that an initial cause, do you think?

KWR Looking back, I was just a really sensitive child. I don't think there was any particular cause, and that can be the thing about clinical depression: there isn't a cause necessarily, other than having a malfunctioning brain on a biological level. Events like having my friends ostracise me certainly exacerbated my sensitivity. We also moved a lot and I never really worked out who I was. I think I would always have got depression, though, and the depression exaggerated those experiences.

When I was a teenager I used to have this world in my head. I'd never feel things. I'd completely shut down. I'd live in this fantasy world, having a conversation with someone but in my head being elsewhere. The only reason that no one noticed I wasn't OK was because I wasn't even sure myself.

And then one day when I was in my late teens I almost stepped out in front of a bus. I wasn't in any way intending to hurt myself; I genuinely believed I was strong enough to take on a bus, which is terrifying. So I went to the doctor, and said, 'Look, I've got this world in my head and I don't think it is quite right.' I was worried I was delusional or something like that. He spoke to me for quite a while and then he did the depression questionnaire (which I've done 6,000 times since!) and he said, 'You're just severely depressed and this is your coping mechanism.'

To be honest it was nice to have the diagnosis. It was nice to know what was going on.

JS Did you get some proper help at that point?

KWR I was staying with my aunt, so it wasn't my normal doctor. He told me to get an appointment when I went home which I didn't do. I thought that now I knew what it was, I'd be fine.

I didn't recognise the impact depression was having on my life for a long time. I was diagnosed at 19 and it wasn't until six years later that I had a breakdown and had to face up to the severity of my health. I'd seen a counsellor a few times but really just carried on. I was a police officer and thought I was madly in love and wanted the security of marriage. It wasn't a healthy or happy relationship and I was so anxious. Then there were the London riots. It broke my brain. When the boyfriend broke up with me I had a severe anxiety attack – banging my head on the wall and screaming – feeling I was about to die. It scared the life out of him. I calmed down, drove home and then went to see my mum and dad. I was signed off work for six months. I was very suicidal, very lonely, utterly broken.

JS You have such a strong faith now, but there was a time you broke up with God. What happened and how did you come to make up?

KWR When I was at university I decided I didn't want to be a Christian any more and went and told my mum. She was so chilled about it that I didn't fight the feeling that something was missing in the way I might have done if she'd been cross.

One day I thought I'd maybe go to the church around the corner from me. They were running a course and even though I thought I knew all the answers, I went. There was one of those really annoying spiritual people who was my leader, and she kept saying things like 'You just have to have faith.' She changed my world! It was very gradual. I'm an external processor so it was good to go through the basics and work out what I thought by talking about it.

JS When your dad Justin Welby became Archbishop of Canterbury you took the opportunity to use your suffering for greater good. Was that a conscious decision?

KWR No, it was totally accidental. I was working for a Christian disability charity, Livability, and my team was the church engagement team, helping the church to serve disadvantaged parts of society more generally. We hadn't explored mental health so I was thinking about writing a blog for work, but it was really personal. I realised it wasn't a work thing any more and decided to put it on my own blog. I sent it to Dad to see what he thought. He said it was good and that it might get picked up. And it did.

JS Which in itself says a lot about how far we have to go...

KWR That the Archbishop's daughter has depression made national news is hilarious and frightening and absurd. That was 2013. It was less than a year since I'd had a major breakdown and I was still really ill.

I never thought of it as brave, but just that it was something we need to talk about. It is something the church has failed at. I've been hurt badly by the church. I feel like there's no way to engage with God in the evangelical church in suffering. You are constantly hearing stories of how someone has overcome or found victory – only completed stories.

As I get older I realise more and more that if I've made a decision I don't know why I've made it. I don't think things through – I jump and then realise how long the drop is! There was an intense month of media – BBC, the Daily Telegraph, a few other bits and pieces. I just did it because I was asked. It made me feel important and I liked the attention.

JS I'm sure people have told you before not to be so harsh on yourself! The search for significance is universally human. We all want to be special. None of us wants to feel like one of 4.7 billion people. But it sounds as if you regret being so open?

KWR Knowing what I know now, I'd be more cautious about the extent to which I shared. I am a natural born over-sharer. I can't help myself! If someone says, 'How are you?' I say, 'I'm really, really depressed...sorry, sorry. Fine. Nice to meet you!' But I'd do it again because I've seen that vulnerability breeds vulnerability. And mutual support and wholeness.

JS I've found that sometimes all you need to do to make an impact is stand up and say, 'I am a Christian and I have suffered from depression.'

KWR It is all you need to do. It has become more of a calling for me through having done it, but I'd advise other people to have caution and a really strong support network.

Dad becoming the Archbishop of Canterbury shook my world. Not because he wasn't right for the job, but because I had no idea what it would mean. And so I recklessly tweeted and blogged without knowing the consequences. Apparently, a lot of people care about the Archbishop.

The Welby bit of me became the draw. I'd do speaking engagements and it really took it out of me to be constantly introduced as 'The Archbishop of Canterbury's daughter, Katharine.' They couldn't even put my name first! It was only as I began to recover that I thought it didn't matter if it meant I could talk about mental health. At that point the invitations began to change.

JS What would you want preachers to know about mental health issues?

KWR That they are not immune to these issues themselves. I've come across a lot of church leaders and preachers willing to engage in the mental health needs of their congregations but not in their own. They are trying to be strong to support others but they are actually putting across the message that it isn't okay to be broken. Self-care is the number one thing a leader needs to do.

Also, you don't need to share everything going on in your life from the front, but it is important to acknowledge when something is going on. So many times I've sat in church and heard again and again and again preaching on the love of God, and other things that are good, but no vulnerability. It has made me feel ashamed, that I shouldn't be depressed. Very rarely is it explicitly expressed that depression is bad, but that idea can be conveyed in many ways. There is a subtle suggestion that God is our strength and he is going to fix us. Often people say and do that because they are trying to convince themselves as much as anyone else. Preachers can make a huge difference by allowing suffering its place in the centre of life, a place where God is with us. We need to stop ignoring brokenness.

I'd also say, please include people with mental health issues in church life. Let them preach. Let them pray. Let them be on teams. I'm particularly unreliable. Some weeks I make it to church and some I don't. In my old church I was on the preaching rota, and I had a deal with the vicar that if I knew I wasn't going to be able to do it, I could just text him. But it made me feel included, and a valid part of the community.

Talk to people and find out how you can include and support them – everyone is different. We don't want to be saying, in effect, 'You're allowed to be broken but the moment you are broken you are not allowed to participate. If you are too broken you can't serve, so hold it all inside. If you are going to explode, go away.'

Acknowledge the pain in the Bible. Not all the suffering in the Bible is because of external circumstance. Elijah is a great one for that. He calls out to God, says 'I wish I was dead' – just after being used in an incredible, miraculous way. God supports him, gets him through the worst bit, and then says, 'Come on, let's keep going.' God doesn't fix him, Elijah is still significantly depressed but God is still talking to him, and calls him to extraordinary things. Who are we to say, 'You are depressed. You can't be used by God.' That's absurd.

If you are a leader and fortunate enough not to have mental health problems, get to know the people who do. Your life will be enriched by those with mental health problems in your church. They may have experienced things beyond your comprehension. It is important to comprehend it if you want to lead well.

This article first appeared in the October edition of Preach magazine, which focuses on mental health, and is reproduced with permission. World Mental Health Day 2018 is today, October 10.