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Laboratory and animal studies suggest lithium could protect the brain from cognitive decline and Alzheimer's disease, but results from human trials have been mixed. To clarify the picture, researchers combined data from multiple clinical trials to test whether pharmaceutical lithium salts have meaningful benefits for brain health.
The authors systematically reviewed and meta-analyzed six randomized, placebo-controlled trials (435 participants) that compared lithium supplementation with placebo for roughly 10 weeks to 24 months. All participants had either mild cognitive impairment, stage of measurable decline that can precede dementia, or diagnosed Alzheimer's disease. The main outcome was change in cognition, prioritizing the Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS-Cog), with the Mini-Mental State Examination (MMSE) used when needed. The tested lithium salts were: lithium carbonate, lithium sulfate, and lithium gluconate.
- When results from all six trials were combined, lithium did not lead to better overall cognitive outcomes than placebo.
- In the primary analysis using the most detailed cognitive test (ADAS-Cog), the average difference between lithium and placebo was small and could not be confidently attributed to the treatment rather than chance.
- Follow-up analyses that relied on different cognitive measures or prioritized different tests reached the same conclusion and showed no consistent cognitive benefit from lithium.
- Measures of behavioral and psychological symptoms of dementia, such as agitation or mood changes, were similar between lithium and placebo groups.
- Subgroup analyses found no consistent benefit based on diagnosis (mild cognitive impairment versus Alzheimer's disease), study length, lithium dose, or lithium salt type.
- One small study suggested a stronger effect from lithium, but it was judged high risk for bias, making its result unreliable.
Lithium's biological effects may depend strongly on its chemical form and how it behaves in the brain. Studies in animals show that lithium can stick to amyloid-β, the protein that forms plaques in Alzheimer's disease. When this happens, lithium becomes trapped inside plaques instead of remaining available to brain cells, where it could help regulate inflammation, communication between neurons, and limiting harmful changes to tau, a structural protein that helps stabilize neurons. Commonly tested lithium forms, especially lithium carbonate, appear more likely to bind to amyloid plaques in this way. By contrast, laboratory and animal studies suggest that lithium orotate, a different chemical form, may enter brain cells more easily and avoid plaque binding.
Importantly, the clinical trials analyzed here did not test lithium orotate, only carbonate, sulfate, and gluconate. As a result, the study supports the conclusion that standard lithium supplements do not slow cognitive decline in people with mild cognitive impairment or Alzheimer's disease, while leaving open the possibility that other lithium formulations could be more effective. In Q&A #69, I discuss the benefits and risks of low-dose lithium supplementation.
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Screen use has become common, even in infancy, yet little is known about how it might influence brain development years later. To address this gap, researchers conducted a longitudinal study to explore how early screen exposure shapes later aspects of mental health.
The study followed 168 children in Singapore from infancy into their teenage years. Parents reported how much time their children typically spent using screens at ages 1 and 2. As the children grew, researchers tracked their brain development using diffusion MRI, a type of brain scan that estimates structural connections between brain regions, at ages 4.5, 6.0, and 7.5. At age 8.5, the children completed a computer-based task that measures several aspects of decision-making, including how people respond to risk and how long they take before making a choice.
- More screen time in infancy aligned with a specific pattern of brain development that was linked to slower decision timing, which in turn was associated with higher anxiety symptoms in adolescence.
- Although the researchers examined multiple brain networks, the association with infant screen time emerged only for the connection between the visual network (involved in processing visual information) and the cognitive control network (involved in things like planning, attention, and self-control).
- Higher infant screen time was associated with a faster drop in "integration" between these two networks from ages 4.5 to 7.5. Higher integration means that these two brain systems tend to work more closely together, while a drop in integration reflects the brain gradually separating their roles as it matures.
- This faster decline in integration appeared to bridge the link between early screen exposure and longer decision times, helping explain why some children took longer before making a choice. Other aspects of their decision-making, such as how accurate or risk-taking they were, did not show the same relationship.
In early childhood, brain networks are still maturing and becoming more specialized in how they interact with one another. Heavy screen exposure early in life may overwhelm developing sensory systems, potentially influencing how visual information is processed as the brain matures. Altered sensory processing may be one pathway linking these brain changes to slower decision-making and higher anxiety later on. Some effects of screen exposure may also operate indirectly, for example by reducing opportunities for parent–child interaction during early development.
The observational design limits causal conclusions. Screen use was parent-reported without detail on content or context, and factors such as sleep, family history, and parent–child interaction were not fully captured. While not definitive, the results underscore early childhood as a sensitive window during which everyday experiences, including screen use, can have lasting developmental effects. In Aliquot #125, Dr. Andrew Huberman and I examine digital engagement, share strategies for managing technology use, and highlight the importance of boundaries for mental health and personal growth.
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Memory retrieval often begins with a brief cue—a single word, a smell, or a sound—but receptivity to such cues may fluctuate from moment to moment due to natural rhythms in the body. To explore this, a research team reexamined previously collected data to see whether the natural breathing rhythm is a factor that shapes how cues lead to successful recall.
The study involved 18 healthy young adults who learned verb–image pairs (verbs linked to either objects or scenes) across two sessions. During later memory tests, participants first judged whether a verb was old or new, then, for recognized verbs, tried to recall the associated image. The team recorded electroencephalography (EEG, a method for measuring brain electrical activity) and airflow-based respiration, then examined how recall outcomes related to specific points in the breathing cycle.
- Associative recall was more likely when the cue verb appeared near the inhalation peak, and accuracy rose again later around the exhalation trough.
- When people successfully recalled the image, brain activity reflected whether the image was an object or a scene, and this distinction was clearest just before the end of an exhale.
- Recall was better when the breathing sequence followed an inhale-then-exhale pattern during retrieval, compared with the reverse order (about 70% vs. 65% recall out of recognized items).
- When recall was successful, alpha and beta brain waves dropped shortly after the cue, a pattern often interpreted as reflecting information processing. These brain waves were also rhythmically modulated by breathing, with additional drops occurring at specific phases of the breathing cycle.
- Simple recognition (old versus new decisions) did not show the same respiratory-phase dependence, suggesting the effect is stronger when retrieval requires reconstructing a specific association.
Breathing in (inhalation) may support the early stage, when the brain takes in and interprets a cue, while breathing out (exhalation) may offer a favorable window for rebuilding the stored memory itself. Together, this indicates that remembering is partly shaped by natural body rhythms and adds to growing evidence that cognitive processes are influenced not only by our senses and activity inside the brain, but also by signals from the rest of the body.
The study was small, correlational, and did not manipulate breathing, so it cannot establish causality. Future work that aligns recall attempts with specific moments in the breathing cycle could test whether breathing directly supports memory retrieval or merely tracks internal state changes. In this clip, Dr. Matthew Walker describes how sound and smell cues played during learning and subsequent sleep can enhance memory formation and retrieval.
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Cognitive abilities such as memory and attention often decline with age, and finding practical ways to slow this process remains a major public health challenge. Many strategies focus on medical risk factors, but less is known about whether social activities can make a difference.
Researchers analyzed more than 20 years of data from the U.S. Health and Retirement Study, which follows a nationally representative group of adults aged 51 and older. Participants repeatedly completed cognitive tests and reported their helping activities. The study focused on two common forms of helping: formal volunteering (unpaid work through organizations) and informal helping (unpaid help given directly to friends, neighbors, or relatives who do not live with the participant).
- Moderate formal volunteering (about 2–4 hours/week) showed the largest short-term improvement. Higher levels also supported cognition, with benefits that appeared to build particularly when volunteering was sustained. The biggest drops occurred when high time commitments to volunteering stopped.
- Informal helping showed a similar overall pattern. Low to moderate time commitments were linked to a slower rate of cognitive decline, and moving to high levels did not add clear long-term benefit beyond moderate involvement, while stopping informal helping was linked to worse cognitive outcomes and faster decline.
These patterns fit with the concept of cognitive reserve, the idea that repeated mental and social demands can help the brain keep functioning as it ages, even as underlying changes occur. Helping others may contribute by regularly engaging attention, decision-making, and social interaction. Helping behavior has also been linked to changes in stress regulation systems and immune functioning.
Although the study cannot prove cause and effect, its focus on within-person changes, timing, and dose strengthens the case that helping itself could contribute to better cognitive aging. In this clip from my appearance on the Modern Wisdom podcast, I detail seven science-based methods for improving cognition.
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Arguments about "brain rot" from TikTok and similar apps often involve anecdotes rather than data. To address this, a new meta-analysis examined whether short-form video use is linked with changes in cognition and mental health.
The researchers combined 71 studies with 98,299 adolescents and adults whose engagement with TikTok or general short-form video use was assessed. The studies assessed how much people engaged with short-form videos and examined how this related to measures of cognition and mental health.
Here are the key results:
- Across all studies, heavier use was moderately associated with poorer cognition overall, with the clearest links for attention and for inhibitory control, the mental ability to suppress impulses and stay on tasks, and weaker links for memory, language, and working memory, while reasoning showed no reliable association.
- On mental health scales, heavier use tracked with small but consistent signs of worse well-being (especially more anxiety and stress), and with weaker links to depression, loneliness, negative mood, and poorer sleep, while self-esteem and body image scores showed no clear pattern.
- Measures that framed use as a behavioral addiction showed stronger associations with both cognitive and mental health problems than metrics that only counted minutes or distinguished users from non-users.
- Correlations were similar in youth and adult samples, and results changed little when studies adjusted for background factors such as age, gender, or other social media use.
Fast, highly stimulating clips may teach the brain to expect constant novelty, which can make slower, effortful tasks and ordinary rewards feel flat. Altered reward circuits, repeated exposure to mental health-themed content, and late-night viewing that disrupts sleep are plausible pathways linking heavier use with difficulties in attention and mood, while the overwhelmingly cross-sectional evidence cannot establish cause and effect.
Taken together, the review suggests that short-form videos appear most concerning when use reflects addictive patterns that interfere with sleep, offline relationships, or tasks requiring sustained attention. Studies that follow users over time and that distinguish types of content and user motivations are needed, so that public debates about "brain rot" can shift from slogans to concrete guidance. In this clip, I discuss concerns about early smartphone and tablet access among kids and its effects on mental health later in life.