Sophie Clark, from Dorset, told her father that she was going for a walk one evening and didn't return home. After her father reported her missing, a member of the public found her hanged the next morning.
Dr Zoe Ellison-Wright, a consultant psychiatrist, told the inquest Sophie had a history of mental health issues, self harm, and had previously tried to kill herself in March 2016 with an overdose of paracetamol and ibuprofen.
The suicide attempt was triggered by the ending of a relationship which worsened the already low mood of Sophie, who described herself as bisexual or pansexual.
'She described pent up feelings and small things made her feel angry,' Ms Ellison-Wright added.
'She said she felt it difficult to concentrate and felt her school grades were dropping she described felling insecure about her body image.
'She said most days she would cut her arms legs and stomach and said it had become an addiction and helped her calm down.
'She had thoughts she would be better off dead because then the pain would go away she thought everyone hated her, including her friends but acknowledged there was no real evidence for this.'
A few months later, in June, Sophie said she was going for a walk at around 6.30pm.
Her worried father contacted the police after 11pm to report her missing and officers began a hunt for the schoolgirl.
The search proved fruitless as efforts to trace her phone signal failed but early the next morning a member of the public, Martin Walker, contacted police to say he had found a young girl hanging in woodland near Sophie's home in Sherborne, Dorset.