"The Arsenal Henry was at Arsenal, now I'm at Barcelona and you won't see the Arsenal Henry any more," the France forward told a news conference at the Nou Camp on Tuesday.
"Barcelona are a different team, with a very different way of playing and I, too, have to play differently.
"Maybe I haven't been at my best level up to now, but I've scored four goals and given three scoring passes. I try to help the team...."
Henry signed a four-year deal with Barcelona in the close season for a fee of 24 million euros ($34.57 million) after spending eight seasons at Arsenal. He had been the focal point at the London club, top-scoring in four of the five Premier League seasons between 2001-06.
"Here they play differently to the way they play at Arsenal. There we played a more direct style and the ball came to me more quickly.
"But I have to adapt to the club and the team and not the other way round and that takes time. Barcelona have played this way for many years, it is their style and I have to adjust to it."
Henry, who spent much of his last season at Arsenal on the sidelines because of injury, said he has been playing with pain in his Achilles tendon for the last three games.
DEFENDED RONALDINHO
The 30-year-old admitted it might have been better if he had made a more gradual return to action this season after such a long lay off.
"Maybe it would have been better to have come into the team more slowly, but with the situation the way it was and with players injured and others coming in late I had to carry out my recuperation at the same time as I was playing."
Henry also defended Barca team mate Ronaldinho who has come under fire after a lacklustre start to the season.
"Ronaldinho has played at top level for a long time but he isn't a robot," he said.
"I don't think he is playing as badly as they are saying. The problem is that expectations are so high. What isn't normal is that Ronaldinho has played at such a high level for such a long time so whenever his performance drops a little people get upset.
"For me Ronaldinho is a very important player for the team because he is a great player and he will always get the attention of the opposition defence and that helps us play."
Asked about the performance of his former Arsenal team mate Cesc Fabregas who has come into his own since Henry's departure, the Frenchman said: "He is an incredible player. He passes, works hard, scores goals and is playing really well."
