The 26-year-old, whose occupation was given as celebrity, was discovered in a park in Enfield, north London, on March 16 this year.
Recording a conclusion of suicide, senior coroner Andrew Walker said: "There were a number of notes left behind and messages in which Mr Thalassitis clearly set out his intention that his life should come to an end."
The inquest heard toxicology results showed there was cocaine, alcohol, paracetamol and antidepressants in his system at the time of his death.
Mr Walker added: "The blood and urine concentrations are consistent with alcohol intoxication."
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Earlier this year a coroner in Tyneside issued a warning about mixing alcohol and cocaine after another Love Island star, Sophie Gradon, hanged herself having consumed both substances.
The coroner at Ms Gradon's inquest said research in the US said the combination was known to make someone 16 times more likely to kill themselves.
Mr Thalassitis was found by a jogger in Church Street Recreation ground next to Haselbury Road in the north London borough where he lived shortly before 9.30am.
She called a friend who advised her to contact the police, the court heard.
An officer who attended the scene said a black notebook had been found near where Mr Thalassitis died.
Giving evidence Pc Emma Clauson said: "I looked through the notebook which was a sort of combination of a diary and letters and positive thoughts.
"At the back of the diary was a number of notes that had been addressed to his family."
Following the hearing the family paid tribute to their "wonderful son and brother ".
Reading a statement on their behalf Dave Read, who was the star's manager and agent, said: "We would like to take this opportunity to thank everyone for their kind messages and support during this very difficult time.
"Today's inquest concluded the sad news at the loss of our beautiful son and brother.
"We would respectfully request privacy at this time and digest what has happened to our family.
"Mike was a wonderful son and brother and will be dearly missed."
Speaking to reporters after the inquest, Ms Brown said it was "important to let his memory live on and to also remember the importance of why this happened and to change your own life on what terrible, terrible, terrible thing has happened to Mike".
Producers paid tribute to Thalassitis at the end of the opening episode of the new series, which aired on Monday night.
Beneath a photo, a message on screen read: "In loving memory of Mike Thalassitis 1993-2019"