Alex Vause landed in jail after working as a drug smuggler for an international cartel. In Season 2, she is released after testifying at the trial of her former boss Kubra. She lands back in jail after she’s caught in possession of a gun by her probation officer (whom Piper tipped off).
Taystee is jailed after becoming involved in Vee’s drug ring. At one point, she is paroled from prison, but finds it hard to adapt to the rough life waiting for her outside of jail. She ends up violating her parole and is consequently sent back to Litchfield.
After growing up in a strict Amish community, Leanne temporarily left her family and got into drugs with a bad crowd. Though she eventually decided to return, she made the mistake of leaving her backpack of incriminating stuff near the outskirts of the town, where the police found it and hauled her in.
As shown in Season 3, Norma fell in love with a cult leader in her younger years. Years later, after all of the other wives had abandoned him, he becomes bitter and verbally abusive. Finally fed up with his insults, she pushes him off a cliff one day in a surge of anger, leading to his death.