i think that obessive thoughts can lead to delusons, especially when people with ocpd get obessed with details about things but miss the bigger picture

. My mother had always been undiagnosed ocpd, and then a few years ago she had a delusional breakdown following an accident. Her " evidence" that doctors were trying to poison her and there was a conspiracy against her for writing a complaint was that she had seen a pile of papers on the doctors desk which obviously were her records and the letter of complaint ( could have been any other pile of paper) that the doctors had his name badge "turned around" so she could not know his name as he killed her and that she had seen a nurse laughing with a doctor , which she took to mean they were planning to do something bad to her.

Tiny little imagined details that my mother latched on to and formed on to a persecutory delusion. when she had the accident i feel like she lost control , she could not admit ultimately that it had been her fault , so to take back that control so she began to blame people around her and obsess over these delusional thoughts. it was better to make a delusion up than face the situation.