Flight Attendant Current
Flight Deck / Cabin / Aircraft Event Passenger Misconduct; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Human Factors
Guest in seat 23F was smoking a cigarette at his seat. 20A came to the back galley and had informed [flight attendants] that there was someone smoking. I immediately went into the main cabin and could smell cigarette smoke. [Flight attendant] and I came across 23F smoking. [Flight attendant] confiscated the cigarette and went to the restroom to extinguish. I told the guest that they cannot smoke on a plane. He informed me that it wasn't his fault and that he did it while he was sleeping. I then confiscated his lighter and told him we will return it when we land and he deplaned. [Flight attendant's] got and presented the disturbance report to the guest.  He was very antsy and would stumble like a zombie to the restroom multiple times before we even performed service. We did not smell any alcohol; I thought maybe he had taken a strong sleeping pill. As the flight went on and after the cigarette incident his behavior became more erratic in being up and about. Even though he had used the restroom at least 15 times he would stumble to the back struggling to find the restroom and door handle. He even would try opening other galley structures. After the incident we as a crew felt it unsafe to leave our doors and had to be vigilant of the guests movements at all times. We had to move the guest seated in 23 A; she felt very uncomfortable and was on edge about the guest. 23 F stumbled and shoved a guest waiting in line for the restroom 9C. I said something to 23F and there was no comprehension of what he did and he just stood there like a zombie. A guest in 29 F was uncomfortable with the guest's behavior and discussed it with me. As a crew we decided for the overall safety of the aircraft to divert to have the guest removed in Chicago. In my personal opinion I believe the guest may have been under the influence of a substance.
Flight Attendant reported a guest smoking and the associated behavior of the guest on the flight.