Is it permissible for one suffering from intrusive thoughts to say: "O Lord, I bear witness, and I ask the bearers of Your Throne to bear witness, that You are Allah, there is no god but You"?

The topic of obsessive thoughts and how to treat them has been previously discussed in earlier fatwas. As for the mentioned dhikr (remembrance), it is one of the narrated supplications, and it has been discussed previously in Fatwa no. 49200.