What is brain fog?

BACKGROUND: The term 'brain fog' is increasingly used colloquially to describe difficulties in the cognitive realm. But what is brain fog? What sort of experiences do people talk about when they talk about brain fog? And, in turn, what might this tell us about potential underlying pathophysiological mechanisms? This study examined first-person descriptions in order to better understand the phenomenology of brain fog. METHODS: Posts containing 'brain fog' were scraped from the social media platform Reddit, using python, over a week in October 2021. We examined descriptions of brain fog, themes of containing subreddits (topic-specific discussion forums), and causal attributions. RESULTS: 1663 posts containing 'brain fog' were identified, 717 meeting inclusion criteria. 141 first person phenomenological descriptions depicted forgetfulness (51), difficulty concentrating (43), dissociative phenomena (34), cognitive 'slowness' and excessive effort (26), communication difficulties (22), 'fuzziness' or pressure (10) and fatigue (9). 50% (363/717) posts were in subreddits concerned with illness and disease: including COVID-19 (87), psychiatric, neurodevelopmental, autoimmune and functional disorders. 134 posts were in subreddits about drug use or discontinuation, and 44 in subreddits about abstention from masturbation. 570 posts included the poster's causal attribution, the most frequent attribution being long COVID in 60/570 (10%). CONCLUSIONS: 'Brain fog' is used on Reddit to describe heterogeneous experiences, including of dissociation, fatigue, forgetfulness and excessive cognitive effort, and in association with a range of illnesses, drugs and behaviours. Encouraging detailed description of these experiences will help us better understand pathophysiological mechanisms underlying cognitive symptoms in health and disease.

‘In a mist?’ – What is ‘brain fog’?

ObjectivesThe term ‘brain fog’ is increasingly used in social and other media. But what is brain fog? What sort of experiences do people talk about when they talk about brain fog? And, in turn, what might this tell us about potential underlying pathophysiological mechanisms? In this study we examined first-person descriptions of brain fog in order to better understand a) the phenomenology of brain fog, and b) the causal attributions of those describing brain fog. We use this information to consider implications for clinical research.MethodsData were scraped from the social media platform Reddit using Python. Posts containing ‘brain fog’ were identified between 27thOctober 2021 and 3rd November 2021. Those not describing or discussing brain fog as a symptom or experience were excluded. Potentially identifying information was removed prior to analysis. We undertook thematic analysis of containing subreddits (topic-specific discussion forums), causal attributions, and discrete brain fog experiences.Results1663 posts including the term ‘brain fog’ were identified, of which 717 met inclusion criteria.44% (315/717) posts originated from subreddits concerned with illness and disease: including COVID-19 (87 posts), autoimmune, functional, neurodevelopmental, major psychiatric, and endocrine disorders. Brain fog was also discussed in subreddits about prescribed and non-prescribed drug use, and subreddits concerned with intentional restriction of masturbation (‘nofap’).141 first person descriptions of brain fog described overlapping concepts including: forgetfulness (51), difficulty concentrating (43), dissociative phenomena (34), perceived cognitive ‘slowness’ and excessive effort (26), communication difficulties (22), a feeling of ‘fuzziness’ or pressure in the head (10), and fatigue (9).570 posts described a perceived cause of brain fog, of which half attributed brain fog to illness or disease (282/570) (the most common single attribution being ‘long COVID’ in 59/570 (10%)), followed by psychiatric conditions in 38/570 (7%). The second most common single attribution of brain fog, in 24/570 (24%), was restriction or excessive masturbation.ConclusionsBrain fog is discussed on the Reddit social media platform in association with a wide range of illnesses, diseases, drugs, and activities. The term is used to describe heterogeneous experiences, which do not map in a straightforward way to the domains enquired about during a ‘cognitive’ clinical examination, but include experiences of dissociation, fatigue, and excessive cognitive effort. Encouraging detailed description of subjective experiences – moving away from a psychometric testing approach and towards a phenomenological approach – might open new routes into understanding cognitive difficulties in health and disease.