Pietro Addis, 19, stabbed grandmother Sue Addis 17 times at her home in Brighton after it was heard she had expressed fears the cannabis-addicted teen was becoming ‘paranoid’.
This happened in January 2021 and faced a murder charge over her death.
The teen has now been cleared of murder after he stabbed his grandmother to death at her home. A trial at Lewes Crown Court saw the jury accept his defence and find the cannabis addict not guilty of murder.
He had previously pleaded guilty to manslaughter and will now be sentenced on May 5.
Addis was found not guilty of murder on the grounds of diminished responsibility on Friday.
According to Mirror, the teen stabbed the 69-year-old 17 times before leaving her body in a bathtub at her home, before calling 999 to turn himself in.
The then-17 year old claimed to have been suffering from ‘transient psychosis’ when he killed Ms Addis on January 7, a jury at Lewes crown court heard during the course of his trial.
The teenager had been living with Ms Addis at the time due to a dispute with his dad over growing cannabis.
On Friday, Addis pleaded not guilty to murder, but admitted manslaughter. During the trial, child forensic psychiatrist Dr Peter Misch told the jury Addis couldn’t think rationally at the time.
‘Pietro was suffering from paranoid psychosis at the material time,’ the psychiatrist.
‘It is a state of mind that is extremely abnormal so it impairs rational thinking and is often associated with abnormal beliefs that are not fixed in reality.
‘Addis had also been diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) in 2018, the court heard, after his grandmother wrote to Dr Daphne Keen expressing her concerns.
‘He is suffering paranoia and we are all getting annoyed with him rather than helping,’ Ms Addis wrote.
‘He still says he can’t do anything without the Elvanse [his ADHD drug] but with the weed as well he has become impossible to reason with,’ she said.
In the days leading up to the alleged murder Mrs Addis told a friend her grandson had been acting ‘strangely’.
He had begun banging on his grandmother’s bedroom door at night telling her he loved her.
A post-mortem examination revealed 17 stab wounds to the body: two to the neck, four to the chest, five to the abdomen, four to the left arm and two to the left leg.
