An EEG recording reflects not only a patient’s clinical state, but also which medications they are taking. Researchers from the Laboratory of Neurophysiology of Mind at the Nencki Institute of Experimental Biology, Polish Academy of Sciences, have conducted the largest analysis of this phenomenon to date worldwide and published the results in the journal eBioMedicine.
The team analysed over 24,000 EEG recordings collected over 20 years at two psychiatric hospitals in Warsaw, covering nearly 75,000 variables describing brain activity and 14 groups of psychotropic medications. Thanks to such a large sample, the researchers were able to detect subtle yet consistent patterns that are difficult to capture in smaller studies.
The analysis confirmed relationships already known from earlier, much smaller-scale studies, while also revealing over a dozen new links between medications and EEG patterns, including:
💊 Benzodiazepines strengthen beta waves (associated with wakefulness and focused attention), while weakening theta waves linked to emotional tension.
💊 SSRI antidepressants increase gamma-wave synchronisation between different brain regions – a process important for integrating sensory stimuli, conscious perception, working memory, and attention.
💊 Anticonvulsants alter the complexity of the EEG signal, reducing alpha-wave synchronisation while increasing it in the theta band.
💊 Antipsychotic medications may lower the brain’s overall arousal level, potentially limiting the processes involved in generating hallucinations.
These findings pave the way for using EEG as a tool to help doctors assess whether a patient is taking their prescribed medication as directed and whether their brain is responding to treatment as expected. They may also support the testing of new psychotropic substances.
The full set of results, along with an interactive way to explore the data, has been made publicly available by the researchers on the BrainwavesRX platform: brainwavesrx.nencki.edu.pl.