Lennon was detained under the Mental Health Act in May after officers found him walking on the side of a thoroughfare near the M602 motorway.
He didn’t play again for Everton for the rest of the season and sought help at the Priory.
And the former Tottenham and Leeds United star is now back in training with the Toffees ahead of the new season.
He wrote: “Hi everyone,
“It’s great to be back after a difficult period. I’ve had a good first week of training and can’t wait to kick on now.
“I want to thank all the staff and patients at The Priory in both Darlington and Altrincham and all the staff at Salford Royal Hospital.
“The support I’ve had from Everton, Spurs, their fans, football fans and concerned members of the general public has been incredible.
“It’s important for me to emphasise that there is amazing help out there and anyone feeling anything out of the ordinary should seek support because it’s great and good to talk.
“Lastly, a special thanks to the staff at Everton, my team-mates, and especially my family and the people around me.
Lennon has not played for the Toffees first team since February, having been in and out of Ronald Koeman’s side for much of last season.
Discussing the winger’s return to training, Koeman said: "Everyone knows he had a hard time at the end of the season.
"It is a good time to start to get his fitness back."
Source: Daily Express