There is tangible relief in Hazel Rolston's riveting biography of her descent into depression, 'Beyond The Edge' when, after four, long wearying years fighting her 'black dog', she clambers back up the abyss and touches normality.

Those who have undergone depression will readily identify with these sentiments: 'I felt as if my captor's tag had finally been removed. I had learnt that, when under stress, I have a tendency to give into old fears and link into well-worn thought patterns. I had to avoid these at all costs, trust that I knew myself better than their voices and ignore them. Now (having seen her psychiatrist) I was being given the tools to end their control'.

Four years earlier, she was far from that happy state of affairs. At critical stages of her life, sudden spasms of physical ill-health caused u-turns in her working career, but it wasn't until she had her first child to her husband, Steve that her depression of the post-natal kind engulfed her. Her daughter, Katherine was prone to bouts of physical ill-health and that, coinciding with her own depression, engendered feelings of inadequacy as a mother, even guilt, and thoughts of suicide.

Readers should know that, having a religious upbringing (her parents were Presbyterian ministers), the author had a strong faith. It was an active faith through which she was able to express herself at 'witness' meetings, although later in her depressive state, her outpourings were so personal and scary that she was advised not to return.

However, the one thing about her strong faith, even if at various times she doubted God was with her in her abyss, was it prevented despair convincing her that suicide was the best way out. The book doesn't contain even one attempt at taking her own life, just episodes of increasing tiredness as Katherine, happily recovered from an op that was causing her ill-health, demanded more attention.

Imagine the scene: her husband, whose aeronautical work takes him all over the place, coming home late, tired and hungry and finding the house in disarray, his wife energy-less and lying exhausted though not through work.

So, her faith played a part, and her husband certainly did, until he too succumbed to depression, though happily of the short-lived variety. But, there were other players and, here, the author stumbled into a minefield as she sought a way out.

To a degree, the family doctor can do so much but, invariably, it's the consultant psychiatrist and their attitude to the patient who play a critical role as do family and friends. In Hazel's case, there was an arms' length relationship with her parents although, to be fair, they helped her materially when she had to cry off work and the family income was reduced.

Friends are also key to the depressive's struggle to find the exit door. The author, being a church goer, was ideally placed in this regard, but a missed opportunity to join a social group of mothers from her ante-natal days closed the door on one possible outlet, as did the aforementioned cold shoulder from church groups whose leaders didn't like her self-analysis.

So that leaves who? Well, as the author reminds us throughout, the most critical person is the sufferer, and how they react.

This is how Hazel saw her own role: 'One of the more positive results of my depression was learning that the discipline of doing things despite feeling terrible was beneficial. I learned that, as long as I was courageous enough to leave my crater, ie my home, my captors did not have total control over me'.

This led her to go along to a Deaf Society meeting and learn sign language ('I felt accepted, known and loved'). Some depressives spurn medication when they start feeling good, but the author wasn't in that group. Where medication, in her case, was effective was during daylight hours but, come night time, her scary thoughts returned.

This is how she neatly puts it: 'I felt as if I was being released from my crater during the day but returning to it at night when my accusers (ie those voices she refers to) would cross-examine me for proof of my innocence.

So, what were those 'scary thoughts'? Well, the author had grown up in Lisburn, a garrison town with attendant IRA attacks throughout the Troubles. She finally was referred to a psychiatrist who related those scary thoughts to her habit, when a wee girl, of ritually closing doors and curtains to protect her family from attack. In that way, she was reducing the threat.

The medics call this, 'magical thinking' and, in the same way, the author dealt with the thought of losing her baby by mentally checking for threat by entering her personal abyss.

This book, it runs to 162 pages, the author dedicates to, 'all those who feel lost in rough terrain and held captive by Despair'. It's a salutary read for those not familiar with depression, and a timely support for those who are.

'Beyond The Edge', which is in paperback and is published by Inter-Varsity Press, is now available from the Evangelical Bookshop, Dublin Road, Enniskillen at the reduced price of £4.99.