Cognitive and affective outcomes of more severe compared to less severe carbon monoxide poisoning

To assess cognitive sequelae, depression and anxiety following carbon monoxide (CO) poisoning.

Prospective cohort study.

This study prospectively followed 256 patients, 55 with less severe and 201 with more severe CO-poisoning. The prevalence of cognitive sequelae, depression and anxiety at 6 weeks, 6 months and 12 months was compared in patients with less severe and more severe CO-poisoning.

Of the less severe CO-poisoned patients, 39% had cognitive sequelae, 21% depression and 30% anxiety at 6 weeks. Of the more severe CO-poisoned patients, 35% had cognitive sequelae, 16% depression and 11% anxiety at 6 weeks. There was no difference in the prevalence of cognitive sequelae at any time. The prevalence of depression was higher in patients with less compared with more severe CO-poisoning at 6 months (p = 0.04), but not 6 weeks or 12 months. The prevalence of anxiety was higher in patients with less compared to more severe CO-poisoning at 6 weeks (p = 0.008), but not 6 or 12 months. Anxiety decreased over time in the less severe group (p < 0.01).

CO-related cognitive sequelae, depression and anxiety are common and may be independent of poisoning severity.