A systematic review of nine retrospective surveys involving 5,419 respondents found that oxygen and subcutaneous triptan injections were most often reported as effective abortive treatments for cluster headache, while psilocybin and lysergic acid diethylamide (LSD) were most commonly reported as effective prophylactic treatments. The reported efficacy of most substances was consistent across different surveys, and the order of efficacy generally agreed with clinical studies. The findings suggest that retrospective surveys can provide supporting information on treatment effects and generate hypotheses about novel therapies. The consistently reported efficacy of psilocybin and LSD in prophylactic treatment indicates a need for clinical studies.
Inhaling 50% nitrous oxide (laughing gas) for one hour and a single low dose of ketamine both alter gene expression in the medial prefrontal cortex of adult mice, particularly affecting regulators of MAPK signaling pathways in pyramidal cells. Nitrous oxide produced much broader and more widespread changes in mRNA expression than ketamine. However, unlike ketamine, nitrous oxide did not increase the firing rate of putative pyramidal neurons or boost gamma brain wave activity. The findings suggest that while both substances share some molecular effects, their neural activity patterns differ markedly.