The former Bill actor was found dead in January by his wife with knife wounds to his wrists, chest and throat.
An inquest heard that the 59-year-old actor had unsuccessfully tried to sell his London home.
Tarrant's partner Sabrina Morris explained that the pair had visited their GP about his depression, brought on by financial struggles.
Detective Constable Adam Smith told the hearing: "Mr Tarrant had not been sleeping and according to Sabrina Morris had become extreme in his behaviour.
"Miss Morris was unable to reason with him and according to Miss Morris, Mr Tarrant had become unwilling to listen to advice on how to deal with the difficulties he was experiencing in selling a property.
"Mr Tarrant was given sleeping tablets and anti-depressants by his doctor. As Mr Tarrant left the surgery he received a telephone call informing him that the sale of his property had fallen through for a second time."
Tarrant's GP Dr Nicholas Ring explained: "I specifically asked him if he had thoughts of suicide but he indicated that although he felt desperate at times he would not consider suicide because of his partner and child."
The inquest confirmed that Tarrant's death was from complications caused by stab wounds.
Colin Tarrant played Inspector Andrew Monroe in the long-running ITV drama, which was axed after 27 years in 2010.
The actor was survived by his partner Sabrina and two sons, Juma and Louis.
The Bill's Jeff Stewart attempted to kill himself on the set of the show in 2008 after learning his character PC Reg Hollis was being axed.