Dr Sharon McDonnell and colleagues at Manchester University have carried out the largest ever survey of suicide bereaved families in the UK.
More than 7,000 people responded, and the results show a third have suffered from mental health problems, and have considered taking their own lives.
Dr McDonnell began researching the subject after losing her brother in 1990, going on to earn a PhD despite leaving school with no qualifications.
Video journalist Alex Dackevych
Animations by Mel Lou