We present a baseline for the CLPsych 2025 A.1 task: classifying self-states in mental health data taken from Reddit. We use few-shot learning with a 4-bit quantized Gemma 2 9B model (Gemma Team, 2024; Brown et al., 2020; Daniel Han and team, 2023) and a data preprocessing step which first identifies relevant sentences indicating self-state evidence, and then performs a binary classification to determine whether the sentence is evidence of an adaptive or maladaptive self-state. This system outperforms our other method which relies on an LLM to highlight spans of variable length independently. We attribute the performance of our model to the benefits of this sentence chunking step for two reasons: partitioning posts into sentences 1) broadly matches the granularity at which self-states were human-annotated and 2) simplifies the task for our language model to a binary classification problem. Our system placed third out of fourteen systems submitted for Task A.1, earning a test-time recall of 0.579.

Methods for lexical semantic-change detection quantify changes in the meaning of words over time. Prior methods have excelled on established benchmarks consisting of pre-selected target words, chosen ahead of time due to the prohibitive cost of manually annotating all words. However, performance measured on small curated wordsets cannot reveal how well these methods perform at discovering semantic changes among the full corpus vocabulary, which is the actual end goal for many applications.In this paper, we implement a top-k setup to evaluate semantic-change discovery despite lacking complete annotations. (At the same time, we also extend the annotations in the commonly used LiverpoolFC and SemEval-EN benchmarks by 85% and 90%, respectively). We deploy our evaluation setup on a battery of semantic-change detection methods under multiple variations.We find that when presented with a natural distribution of instances, all the methods struggle at ranking known large changes higher than other words in the vocabulary. Furthermore, we manually verify that the majority of words with high detected-change scores in LiverpoolFC do not actually experience meaning changes. In fact, for most of the methods, less than a half of the highest-ranked changes were determined to have changed in meaning. Given the large performance discrepancies between existing benchmark results and discovery “in the wild”, we recommend that researchers direct more attention to semantic-change discovery and include it in their suite of evaluations. Our annotations and code for running evaluations are available at https://github.com/khonzoda/semantic-change-discovery-emnlp2025.