Repeated low doses of psilocybin reduces perceived symptom severity of obsessive-compulsive disorder, but fails to restore cognitive flexibility: A case study of identical twins

Background: Obsessive-Compulsive Disorder (OCD) presents significant challenges to individuals mental health, characterized by intrusive thoughts and repetitive maladaptive behaviours. Recent exploration into alternative treatments has spotlighted psychedelics, notably psilocybin, for their potential therapeutic benefits in different psychiatric disorders, including OCD. This case study delves into the effects of low doses of psilocybin, with no subjective psychedelic effects, commonly referred to as microdoses, on symptom alleviation and cognitive flexibility in OCD, focusing on a pair of identical twins discordant for the disorder.Case presentation: The study documents the experiences of one twin diagnosed with OCD who embarked on a regimen of psilocybin low doses, while the other twin, unaffected by OCD, served as a control. Qualitative and quantitative measures were employed to assess changes in symptom severity and cognitive flexibility following a period of self-administered low doses of psilocybin. The affected twin reported a notable reduction in OCD symptomatology, accompanied by subjective reports of improved emotional regulation and overall well-being. However, despite these symptomatic improvements, cognitive flexibility deficits associated with OCD were still present compared to the unaffected twin.Conclusion: This case study underscores the potential of psilocybin low doses as a promising avenue for mitigating symptoms of OCD. Nevertheless, the observed disparity in cognitive flexibility highlights the nuanced nature of OCD pathology, suggesting that while non-psychedelic doses of psilocybin may alleviate certain symptoms, it may not fully address underlying cognitive impairments. Further research employing larger sample sizes and rigorous longitudinal designs is imperative to elucidate the mechanisms underlying the therapeutic effects of psilocybin low doses in OCD, offering insights into its broader applicability as a treatment modality.