Ilicic has been missing for Atalanta’s last three matches against Venezia, Inter Milan and Lazio.
The 33-year-old Slovenia international contemplated retirement two years ago when his struggles with depression first came to light but he recovered and has made 23 appearances across all competitions this season, scoring four goals and providing five assists.
But Ilicic has suffered a relapse and Gasperini says the former Fiorentina and Palermo man will be given all the support he needs to make a comeback.
“It is never easy for me to talk about a situation like this, because it is very personal. I can only say we will always be close to him, because these are situations that go beyond football, beyond the profession,” Gasperini told Sky Sport Italia.
“We have known him for many years, had many happy moments together. I can say he is a very normal, positive person, but the insides of our minds are like a jungle. It’s tough for psychiatrists to work out what’s going on, let alone for us.
“I just hope he can return and rediscover some joy playing on the pitch.”
Asked whether Ilicic could terminate his contract and retire, Gasperini added: “He knows as a person we’ll wait for him forever. As a player, I cannot answer that, it’s all very unpredictable and delicate.”
