This is why we must not decriminalise cannabis

By the Editorial Team · Wednesday, July 22, 2026

Simon Carter was indefinitely detained in a secure psychiatric unit after pleading guilty to manslaughter for killing his mother, a crime the judge linked to Carter’s habitual cannabis use and resulting paranoid schizophrenia. The judge condemned campaigns to decriminalize cannabis, warning that the drug contributes to severe mental health problems and citing this case to challenge policy changes.

A judge at Chester Crown Court has criticized campaigns to decriminalize cannabis following the case of a man who killed his mother after developing paranoid schizophrenia, which the judge attributed in part to habitual cannabis use.

Simon Carter, 50, traveled approximately 245 miles from his rented accommodation in Devon to Macclesfield, Cheshire, where he fatally assaulted his 73-year-old mother, Gwyneth Carter, in July 2025. The violent attack resulted in multiple head and neck injuries, and Carter sustained a broken hand during the incident.

Prior to the assault, Carter had admitted himself to a hospital with a history of cannabis abuse and claims of being attacked and forcibly injected with heroin. However, medical staff released him because there was no legal basis to detain him at the time. Subsequent psychiatric evaluation diagnosed him with paranoid schizophrenia and delusional beliefs.

Carter, who had been estranged from his family since 2006 and was unaware of his father Norman’s death, was described by his mother as acting unusually during his unexpected visit. After a brief stay at a mental health facility, he returned carrying a saw and was seen loitering near his mother’s home. Neighbors reported hearing loud banging and shouting on the day of the assault. Mrs. Carter’s body was discovered two days later by her sister.

At sentencing, Judge Steven Everett ordered Carter to be detained indefinitely in a secure psychiatric unit after he pleaded guilty to manslaughter on the grounds of diminished responsibility. The judge used the case to publicly express concern about the risks associated with cannabis use, stating that the drug “causes and exacerbates mental health issues.” He added that efforts to decriminalize cannabis, supported by public figures including London Mayor Sadiq Khan and Green Party politician Zack Polanski, were “wholly misconceived.”

The case highlights the ongoing debate around cannabis policy and its potential impact on mental health, with the judge emphasizing the link between cannabis use and serious psychiatric conditions in this and other similar cases.

This article was reported by synthesizing coverage from multiple independent news outlets to present a balanced, unbiased account. Read about our editorial standards. Spotted an error? Let us know.