A qualitative psychoanalytic clinical research project using a post-Kleinian contemporary approach was undertaken by a team of seven qualified and experienced child psychotherapists working in community Tier 3 Child and Adolescent Mental Health Services (CAMHS). A number of referred young people who deliberately harmed themselves or attempted suicide, who fulfilled the inclusion criteria and consented to participate, were offered an extended individual and family assessment. Grounded Theory analysis of the qualitative data led to the formulation of the Truth Danger Theory. Typical situations in which suicidal behaviour occurred were identified, including intergenerational confusion, neglect, physical and/or sexual abuse within the family, Oedipal conflict, maternal depression and families in which there was a chronically ill sibling. We found that there was a marked disparity between the young person's experience of relationships in the family and the family's own account of their situation, a "fractured reality". This can be reflected in an incongruence in the young person's presentation, which may be misleading when assessing risk. The young person feels him/herself to be in a dead end from which there seems to be no escape. Self-harm, for some, contains this impossible dilemma (albeit pathologically) but when it does not, suicide may seem the only option. The Truth Danger Theory provides explanations and predictions for suicidal behaviour and has implications for clinical practice. (Contains 2 notes.)