Future directions for clinical psilocybin research: The relaxed symptom network

Objective: Recent clinical trials have demonstrated that psilocybin may have strong antidepressant effects, and may be effective in the treatment of depressive disorders when embedded in a psychotherapeutic protocol (psilocybin-assisted psychotherapy; PAP). However, despite promising results, the mechanism(s) that may be responsible for the antidepressant effects of PAP remain contested. Within this article, it is argued that the ‘Network Theory of Mental Disorders’ may be a useful tool for clinical research with psilocybin, and may help elucidate the antidepressant elements of PAP. Method: The clinical research using PAP for depressive disorders is briefly summarised, as are the potential mechanisms of PAP. In addition to this, the fundamental tenets of the network theory is presented, with particular reference to depression. In brief, the network theory proposes that depression is an emergent phenomenon, due to strong interactions in a complex dynamic symptom network. Results: A model of action based on a symptom network is proposed. It is hypothesised that, if PAP is successful, the connections between symptoms in a network will weaken, thereby rendering the patient less vulnerable to developing/relapsing into depression. It is argued that the application of the network theory may ultimately improve responsiveness and reduce relapse in PAP. Practical guidance in using the network theory for future clinical research with psilocybin is also provided. Conclusion: This article presents the primary hypothesis of the authors (The Relaxed Symptom Network), and intends to inform future researchers on how to integrate the network theory with future clinical studies using PAP.