Thaniyavarthanam (English: The Repeating Rhythm) is a 1987 Malayalam language psychological drama film written by A. K. Lohithadas and directed by Sibi Malayil.

It stars Mammootty as school teacher Balagopalan, Thilakan as the uncle of the matrilineal family, Mukesh as Gopinathan, and Kaviyoor Ponnamma.

It is a traditional matrilineal society in which the karnavar, the elder one, in the family takes decisions and holds power.

Balan has another uncle, Sreedharan, who is locked up and chained in a dark room in the house as he is considered to be mentally challenged.

Villagers start suspecting Balan of following the footsteps of his ancestors into madness as Sreedharan too had fallen mentally ill with a nightmare.

The family fixes the marriage of his younger sister while hiding the fact she has a "challenged" elder brother.

Balan's mother eventually poisons him and kills him on the day of the ritual for forgiveness from the goddess - to free him from the world.

The movie deals with certain psychological themes and the toxic nature of society in the olden days.

The scrutiny of society coupled with the traditional mindset of the people back then led to Balagopalan's downfall.

[8] Director Ram cited Thaniyavarthanam as his reason for casting Mammootty as the lead in Peranbu.

[10] Director Bala, in an interview mentioned that, inspired by the climax of this movie, he wrote the story of the film Nandhaa.