Is it permissible to memorize the Qur’an with the intention of helping to stimulate the mind and combat its weakness?

A person is permitted, when memorizing the Qur'an, to intend worldly benefits such as "psychological tranquility, acquiring linguistic skills, and soundness of thought," alongside the intention of reward and recompense. For Allah may combine for His servants, through an act of worship, both worldly and otherworldly benefits.

However, if one intends by memorizing the Qur'an merely to combat mental weakness without being mindful of the virtue of memorizing the Qur'an and seeking reward, then he will only get what he intended. And he bears the sin of intending worldly gain through an act meant for the Hereafter.