Is seeking refuge (isti‘adha), saying "I believe in Allah and His Messengers," and spitting to one's left when experiencing intrusive thoughts (waswasa) obligatory or recommended?

For someone afflicted by obsessive doubts (waswas), it is sunnah to seek refuge [with Allah] and say: "I believe in Allah and His messengers." Similarly, it is recommended to spit lightly to the left three times when the devil causes waswas during prayer.