A Nigerian man has been sent to a mental institute in Kano state after he declared that he did not believe in God, according to a humanist charity.
Mubarak Bala, 29, is said to have been forcibly medicated by his Muslim relatives, despite being given a clean bill of health by a doctor.
The International Humanist and Ethical Union say a Lagos-based group has asked a lawyer to take up his case.
Kano is a mainly Muslim state and adopted Sharia (Islamic law) in 2000.
The IHEU says that when Mr Bala told relatives he did not believe in God, they asked a doctor if he was mentally ill.
Despite being told that he was not unwell, Mr Bala's family then went to a second doctor, who declared that his atheism was a side-effect of suffering a personality change, the group says.
Mr Bala, a chemical engineering graduate, was forcibly committed to a mental institution, but was able to contact activists using a smuggled phone.
IHEU spokesman Bob Churchill said the group was concerned about his "deteriorating condition" and called for his "swift release".