I know. I know. Its only a rat study but it does hold out the hope that exogenous ketone supplements can have a similar effect on humans.
Full article here - Exogenous Ketone Supplements Reduce Anxiety-Related Behavior in Sprague-Dawley and Wistar Albino Glaxo/Rijswijk Rats
Currently you can buy exogenous ketones online but they are pretty expensive otherwise I'd be inclined to experiment on myself :)
Since many of the benefits of ketosis are mechanistically attributable to the ketone bodies, it is possible that exogenous ketone supplementation could mimic the therapeutic efficacy of the KD for certain disorders, including anxiety disorders, or other disorders, such as seizure disorders and AD that have a comorbidity of anxiety.
Full article here - Exogenous Ketone Supplements Reduce Anxiety-Related Behavior in Sprague-Dawley and Wistar Albino Glaxo/Rijswijk Rats
Currently you can buy exogenous ketones online but they are pretty expensive otherwise I'd be inclined to experiment on myself :)