On Wednesday, Mar 10, Couzens was screened by mental health nurse Lucy Keating, as he had told custody staff that he "experiences anxiety and depression".
He did not have a history of mental health problems and he did not appear to have any acute mental health concerns that would warrant diversion from the criminal justice system, the Old Bailey heard.
At midday, whilst in custody at Wandsworth Police Station, he was further arrested on suspicion of the murder of Sarah Everard.
At 2:39pm whilst on 30-minute checks and being monitored via CCTV, just as he was about to be taken for interview, he deliberately hit his head on the toilet bowl in his cell, sustained a cut to his head.
The London Ambulance Service was called and he was taken to St George’s Hospital for treatment.
He underwent a CT scan and was treated with sutures for a wound just above his forehead.
He remained under police guard and close supervision whilst in hospital.
He was discharged at 7.15pm and returned to the police station where he was placed under constant supervision.
The following day, on Thursday, Mar 11, at 02.37am, Couzens was assessed by a senior nurse.
Couzens said that he had no diagnosed past medical or mental health history, but that he had been feeling stressed and depressed and had discussed this with his GP at the beginning of the week.
He declared that he had had suicidal thoughts for about two weeks, but had not had a chance to discuss this with any GP or healthcare professional.
Couzens was then interviewed between 5.48pm and 7.55pm - with two short breaks - in the presence of his solicitor and an appropriate adult.
When asked if he understood the caution, he said: “I think so, I don’t know, I think so”.
When asked how he was feeling he said: “I’m in a dark place”.
When asked again, the killer said that he did not know how he felt and he could not judge whether he was fit and well enough to be taking part in the interview.
His solicitor intervened and the interview was paused for a short time to allow a consultation to take place.
When the interview resumed, he answered “no comment” to all questions asked.
Couzens was further interviewed between 8.45pm and 9.42pm.
He continued to answer “no comment” to all questions asked.
On Friday Mar 12, shortly after 10am, Couzens once again deliberately hurt his head.
This time, he intentionally ran into a wall in his cell, causing another cut to his head - a deep laceration to his left eyebrow and swelling around it.
Whilst being assessed by a nurse, he tried again to self-harm by banging his head against the wall as they waited for an ambulance.
He was taken to hospital and treated, returned to the police station to be interviewed between 6.08pm and 6.20pm, where he continued to answer "no comment".
Wayne Couzens was charged with the murder and kidnap of Sarah Everard on the evening of Mar 12.
He made no reply to caution.
Mr Little QC told the Old Bailey: "He remained quiet with a lowered gaze, but answered questions politely when prompted.
"He was placed under constant watch until he first appeared in the Magistrates' court the following morning."
On Thursday, Mar 18, a diving search team was tasked to search the flood relief channel connected to the River Stour, which runs alongside Fellowship Walk in Sandwich.
This is where Wayne Couzens had walked along the riverbank on the morning of Mar 4, hours after killing Sarah Everard.
A police officer entered the water and emerged five minutes later having found a silver iPhone The handset was forensically examined, and identified as Sarah Everard’s Apple iPhone.
The handset did not contain a SIM card.
Sarah Everard murder: Wayne Couzens 'may have abused lockdown powers to arrest and kidnap victim'
