Pakistan's top court has ruled that schizophrenia does not fall within its legal definition of mental illness, clearing the way for the execution of a mentally ill man.

Doctors in 2012 certified Imdad Ali as being a paranoid schizophrenic, after he was sentenced to death for the 2001 murder of a cleric.

His lawyers say the 50-year-old man is unable to understand his crime and punishment.

But in a ruling issued on October 21, the Supreme Court said schizophrenia is "a recoverable disease, which, in all the cases, does not fall within the definition of 'mental disorder'."

Pakistan has executed more than 400 of an estimated 8,000 death row prisoners since reintroducing the death penalty in 2014, according to the Human Rights Commission of Pakistan.

Ali could now be executed as early as next week.

Based on reporting by Reuters and dpa