Aims: The aim of this thesis was to examine existing litteratur regarding the current research interest in psychedelics, more specifically psilocybin, as results in this field show promising preliminary results. This was done in an attempt to answer the following research question:
What does research from the psychedelic renaissance show about the effects of psilocybin, and which implications does this entail in regards to psychological diagnostics and treatment?
The general objective of the thesis was to synthesize existing litteratur to enrich and display nuances in the current understanding of psilocybin, in an attempt to provide sufficient preliminary evidence for the drugs potential usefulness in ameliorating symptoms in a wide range of psychological problems in present times.
Methods: The method used to accomplish the objectives was a integrative review framework, focusing on integration of diverse methodological sources in an attempt to provide a satisfactory depiction of both the neurobiological, aswell as the phenomenological effects, that psilocybin has. 2 search strategies were used, differing in the targeted population, either healthy or clinical participants, and where conducted in several databases pertaining to a wide range of health sciences, and databases containing gray litterature
The retrieved articles data were extracted and analysed following the framework provided by Whittemore & Knafl, 2005, by the Constant Comparison-method, and by following a goal of thematical synthesis.
Results: The literature searches resulted in a total of 3.206 articles which ,through the screening process, ultimately got reduced til a selected total of 86 articles, 31 resulting from the search in the clinical population, and 55 from the search in the healthy population.
The final synthesis resulted in 3 themes; the neurobiological effects, the general effects, and the treatment effects, of psilocybin.
The neurobiological effects mainly showed the potential of psilocybin to agonistically target mainly the 5-HT2A receptor, which in turn caused decreases in observed cortical activity, a change in functional connectivity between networks of the brain, and overall effects on cognition.

In regards to general effects were mentioned several acute, subacute and long-term effects, either negative or positive, in regards to the intake of psilocybin. To mention a few; changes in different personality traits, personal values, opinions, moodstates, percepts, prosocial attitudes, altruism, and more.
Finally the treatment effects of psilocybin are mainly shown in clinical populations diagnosed with; anxiety or depression in patients with life-treatening diagnoses, treatment resistant depression or addictions to tobacco or alcohol. Herein are observed clinically significant results in regards to reduction of symptoms, providing a preliminary understanding of psilocybins potential as an adjunct to current treatment paradigms.
Conclusion: The found themes were discussed in regards to current theoretical understandings of the psychedelic state, and the proclaimed necessity of mystical-type experiences and the dissolution of the ego for the observed positive outcomes. Past and present LSD-studies are also compared in an attempt to point out similarities in observed outcomes, so as ascertain whether or not an existing hypothesis regarding the 5-HT2A receptors’ main role in amelioration of the clinical diagnoses bears any weight.
Ultimately, implications for future research, current practice, education and policy are discussed, wherein it is mainly noted, that the future research should focus on more validity and reliability of their results through robust scientific practice and an attempt to introduce sufficient blind-conditions. Furthermore, a focus on recruiting bigger and more heterogenous samples in an attempt to highten generalizabilty should be adopted.