1965 turned out to be yet another eventful year for the Beatles

1965 turned out to be yet another eventful year for the Beatles. They received MBEs (Member of the Order of the British Empire) from the Queen (Lennon returned his in 1969), they played in front of 56,000 hysterical fans at the Shea Stadium in New York, they met Elvis Presley and participated in the filming of their second movie Help! on locations all around the world.
And they had of course new records to make.
It's worth taking into consideration how young the Beatles still were at this point. In 1965, Harrison, the youngest, had just turned 22, McCartney was turning 23, while Lennon and Starr were going on 25.
As young men in their early 20s the Beatles had conquered the hearts and minds of a whole generation of record buyers worldwide. In addition, John Lennon and Paul McCartney had established themselves as the world's most gifted song writers, although now writing songs more independently from each other.
The Beatles were always looking for new directions and new influences, that's why their records sound so different. And 1965 marked yet another turning point in their musical development.

That year, John Lennon and George Harrison had been introduced to LSD, a dangerous chemical drug which had gained popularity among certain artists and intellectuals in the USA. LSD was supposed to inspire artistic creativity through hallucinating experiences, but the drug had nasty side effects and destroyed some of the finest pop talents at the time, including Brian Wilson of the Beach Boys.
The Beatles, in particular Lennon and Harrison, would start taking the drug regularly between 1966 and 1968, but they were fortunate enough to escape any form of lifelong mental illness.
Another sign of the Beatles' new musical direction came with the release of the single Ticket To Ride in April 1965. Penned mostly by Lennon, the song had a slower tempo and a more passive approach than earlier Beatles singles. It was also 3 minutes long, which was considered over the "radio friendly" limit. Ticket To Ride "only" topped the US charts for one week, before it was replaced by Help Me Rhonda by the Beach Boys. In the UK, the single held the no 1 spot for three weeks.

Ticket To Ride was followed by the movie and soundtrack album Help!, released in the summer of 1965. On the new album, two songs in particular pointed to a new direction in the Beatles' music. Help!, the title track, was according to Lennon himself a deeply personal song, which described his emotions and anxieties at the time. You've Got To Hide Tour Love Away, also written by Lennon, was a Dylan inspired folk-rock song, which appeared to be somewhat critical of mainstream society.

The album also featured Paul McCartney's perhaps most famous Beatles song to date, Yesterday, which became a mayor hit in the US (it was the Beatles' 10th no 1 single in the US), and still is one the most played songs on American radio stations.

On the American version of Help!, some songs were, oddly enough, replaced by instrumental soundtrack cuts by producer George Martin. Nevertheless, the album topped both American and British charts for nine weeks.