The psychedelic afterglow phenomenon: a systematic review of subacute effects of classic serotonergic psychedelics

Summary & key facts

Researchers reviewed 48 studies with about 1,800 adults to see what happens in the days and weeks after people use classic psychedelics like psilocybin, LSD, or ayahuasca. They looked at effects that showed up between one day and one month after use. Overall, many studies found short-term improvements such as better mood, greater wellbeing, more mindfulness, closer social feelings, and positive behavior changes. Some people also reported side effects like headaches, sleep problems, or increased psychological distress. No life-threatening or very serious harms were reported, but the studies often did not check side effects in a consistent way. We still do not know which people are most likely to get benefits or whether the short-term improvements turn into long-lasting mental health changes.

Key facts:

• The review combined 48 studies that included about 1,800 adults who had used classic serotonergic psychedelics.
• Researchers focused on the subacute window, meaning effects that happened from one day up to one month after taking the drug.
• Many studies reported reductions in various psychological symptoms and improvements in wellbeing and mood after the acute drug effects wore off.
• Studies also found increases in mindfulness, a stronger sense of connection to others, more spirituality, and some positive changes in behavior.
• Changes in personality, values, and creativity were mixed across studies and did not show a clear pattern.
• Reported subacute side effects included headaches, sleep disturbances, and some cases of increased psychological distress.
• No serious adverse events were reported in the reviewed studies, but many studies did not use a consistent method to record side effects.
• The authors say future research is needed to find who benefits most and whether these short-term improvements lead to long-term mental health gains.

Abstract

Background: Classic serotonergic psychedelics have anecdotally been reported to show a characteristic pattern of subacute effects that persist after the acute effects of the substance have subsided. These transient effects, sometimes labeled as the 'psychedelic afterglow', have been suggested to be associated with enhanced effectiveness of psychotherapeutic interventions in the subacute period. Objectives: This systematic review provides an overview of subacute effects of psychedelics. Methods: Electronic databases (MEDLINE, Web of Science Core Collection) were searched for studies that assessed the effects of psychedelics (LSD, psilocybin, DMT, 5-MeO-DMT, mescaline, or ayahuasca) on psychological outcome measures and subacute adverse effects in human adults between 1950 and August 2021, occurring between 1 day and 1 month after drug use. Results: Forty-eight studies including a total number of 1,774 participants were eligible for review. Taken together, the following subacute effects were observed: reductions in different psychopathological symptoms; increases in wellbeing, mood, mindfulness, social measures, spirituality, and positive behavioral changes; mixed changes in personality/values/attitudes, and creativity/flexibility. Subacute adverse effects comprised a wide range of complaints, including headaches, sleep disturbances, and individual cases of increased psychological distress. Discussion: Results support narrative reports of a subacute psychedelic 'afterglow' phenomenon comprising potentially beneficial changes in the perception of self, others, and the environment. Subacute adverse events were mild to severe, and no serious adverse events were reported. Many studies, however, lacked a standardized assessment of adverse effects. Future studies are needed to investigate the role of possible moderator variables and to reveal if and how positive effects from the subacute window may consolidate into long-term mental health benefits.

Topics

Forensic Toxicology and Drug Analysis Paranormal Experiences and Beliefs Psychedelics and Drug Studies

Categories

Clinical Psychology Psychology Social Sciences

Tags

Adverse effect Anxiety Clinical psychology Hallucinogen Internal medicine Medicine Mood Psilocybin Psychiatry Psychology

Substances

Ayahuasca LSD Psilocybin

Conditions & symptoms

Anxiety Depression Anxiety or worry Feeling disconnected from others Poor sleep Sadness or low mood