Nicolas Leenaerts @nicolasleenaerts.bsky.social · 18/05/2026After 10 months as a postdoctoral researcher at Harvard University in the USA, I'm starting a new role as a psychiatrist at UPC KU Leuven in Belgium, focusing on addiction care while continuing my research on smartphone-based treatments for substance use. Looking forward to this new adventure! 2100
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 16/05/2026Loved working on this project, the perfect mix of clinical impact and methodological rigor! Read the paper to learn how to: 1️⃣ Integrate #OpenScience in #ML 2️⃣ Build an analysis pipeline on simulated data 3️⃣ Calculate features set size & select features 4️⃣ Do a proper decision curve analysis 040
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 17/04/2026Had the pleasure to visit the @d3center.bsky.social at UMich yesterday! Everybody there is amazing. It was great talking and brain storming with you all. I am looking forward to seeing each other again soon. 010
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 19/03/2026Abstract for a presentation got accepted! Come to the SAA conference and hear me talk about how you can use offline reinforcement learning to create better decision rules for JITAIs! 481
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 14/03/2026The first phase of the WARN-D machine learning competition is over! Congrats to the organizers! Before the results are made public, I’m sharing my experiences as a contestant, along with thoughts on the competition’s strengths and limitations. Link: nicolasleenaerts.github.io/posts/2026/3...nicolasleenaerts.github.ioA contestant’s view on the WARN-D machine learning competition: Pros and worrisome consOn January 7 2026, the WARN-D machine learning competition went live on Codabench (link). Researchers from around the world were invited to build prediction models to forecast depression onset in youn... 230
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 03/03/2026When you submit a bunch of jobs to the compute cluster...media.tenor.coma witch is standing in front of a window and says " fly my pretties "ALT: a witch is standing in front of a window and says " fly my pretties " 000
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 02/03/2026The rise of reinforcement learning algorithms in psychology and psychiatry must integrate open science practices! I am therefore proud to present the preregistration of our study using off-policy reinforcement learning to improve JITAIs for weight loss: osf.io/6wpu4/overviewosf.ioOSF 040
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 27/02/2026Picture from the MAPCI training institute I was lucky to attend. A great initiative from the @d3center.bsky.social. If you're interested in learning about adaptive interventions for cancer control, be sure to attend next year! 010
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 20/02/2026Meta-analysis finds a relation between spirituality and a reduced risk of harmful alcohol and drug use. However, is there a difference between religions banning alcohol and drugs and those that do not? Also, this does not prove that promoting spirituality reduces the risk of substance use.jamanetwork.comSpirituality and Harmful or Hazardous Alcohol and Other Drug UseThis meta-analysis synthesizes findings about spirituality and alcohol and other drug use to estimate the overall effect size of the associated risk reduction. 000
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 11/02/2026Saw another paper reporting out-of-sample R² as the squared correlation between predictions and outcomes. That’s wrong! Correlation measures association, not accuracy. It doesn’t tell you how close predictions are. #machinelearning #ML 001
Reposted by Nicolas LeenaertsAaron Fisher @aaronjfisher.bsky.social · 05/02/2026Have you been interested in any of the set theory stuff I've been doing recently? Wondered at all how you can get in on the fun? Here's an R package @nicolasleenaerts.bsky.social and I built called 'setweaver.' This vignette should get you up and running. Yay :) cran.r-project.org/web/packages...cran.r-project.orgsetweaver 1155
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 26/01/2026If you want some music playing in the background while you work (something stimulating but not too much), I can’t recommend Telemann’s Tafelmusik highly enough. It was literally written to be background music! www.youtube.com/watch?v=xNFk...youtube.comTelemann: Complete TafelmusikYouTube video by Brilliant Classics 010
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 25/01/2026As somebody with a mole near their left tear duct, let me tell you this hit a little too close to home 🫠 And to hear this for the first time at 32 😵 000
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 23/01/2026Really interesting paper for everybody dealing with missing data. 120
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 23/01/2026Watch our symposium at #TIPS2025 where I, @emmadeschuyteneer.bsky.social, and Chunzhuo Wang presented our work on using #AI to treat #eatingdisorders and #obesity. www.youtube.com/watch?v=TAVS...youtube.com 010
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 20/01/2026I'm having some disappointing initial results using LLM's/foundation models for intensive longitudinal data in patients with a psychiatric disorder. Hit me up if you are having more luck or want to commiserate! 001
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 19/01/2026Harvard in the snow... Oh and I'm also in the picture. 030
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 13/01/2026Analysis pipeline using off-policy offline RL to improve JITAIs for weight loss is done! Will release the preregistration by the end of the month! Be on the lookout! 020
Reposted by Nicolas LeenaertsEiko Fried @eikofried.bsky.social · 07/01/2026After 5 years of data collection, our WARN-D machine learning competition to forecast depression onset is now LIVE! We hope many of you will participate—we have incredibly rich data. If you share a single thing of my lab this year, please make it this competition. eiko-fried.com/warn-d-machi...eiko-fried.comWARN-D machine learning competition is live » Eiko FriedIf you share one single thing of our team in 2026—on social media or per email with your colleagues—please let it be this machine learning competition. It was half a decade of work to get here, especi... 5190160
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 14/12/2025Snapshots from our symposium at #TIPS2025 where I, @emmadeschuyteneer.bsky.social, and Chunzhuo Wang presented our work on using #AI to treat #eatingdisorders and #obesity. 030
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 10/12/2025Want life tips? Well, you won’t get them from me. But if you want to hear me talk about using AI to address eating behaviors, join me at #TIPS2025. 030
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 09/12/2025Here @mcleanhospital.bsky.social with Tori Votaw to give a presentation on using reinforcement learning to improve JITAIs for cannabis use! 020
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 02/12/2025We used LLM's to {insert topic here}. 010
Reposted by Nicolas LeenaertsSociety for Ambulatory Assessment @ambulatory-assessment.org · 01/12/2025Join us in Vienna next year for #SAA2026. Abstract submissions are now open: univie.eventsair.com/saa2026/subm...univie.eventsair.comAbstract Submission - Society for Ambulatory Assessment conference (SAA 2026) - OMP, University of Vienna 041
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 25/11/2025‘It being Monday’ is showing up as the strongest predictor for a negative outcome in my dataset. Who am I modeling? Garfield? 🐈 061
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 25/11/2025Got selected as a MAPCI 2026 fellow! Really excited to learn how to develop JITAIs for cancer survivors struggling with substance use! 030
Reposted by Nicolas Leenaertsd3center @d3center.bsky.social · 11/11/2025Only 3 days left to apply! MAPCI is a free, comprehensive training program (Feb 24–27, 2026 • Ann Arbor) for cancer control researchers developing adaptive interventions (including JITAIs in mobile health). Significant travel & lodging support. Apply by Nov 14, 2025 → mapci.space 011
Reposted by Nicolas LeenaertsJonas Dora @jonasdora.bsky.social · 17/11/2025Our experimental study on the effects of negative mood and alcohol intoxication on reinforcement learning in the Iowa Gambling Task is now published OA in Judgment and Decision Making: doi.org/10.1017/jdm.... as always, anonymized data, materials, and code can be found on the OSF: osf.io/ky3aj/doi.orgAlcohol intoxication and negative mood similarly affect reward learning but not punishment learning in the Iowa gambling task | Judgment and Decision Making | Cambridge CoreAlcohol intoxication and negative mood similarly affect reward learning but not punishment learning in the Iowa gambling task - Volume 20 1124
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 23/11/2025Surely we can all agree that having Black Friday deals for GLP-1 agonists is just not OK. 030
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 22/11/2025I love that LLMs can help the new generation with coding, but it's making me feel like an old guy every time I say: 'Back in my day, we had to go to Stack Overflow and hope somebody already posted about this problem, and that someone else actually had a helpful response.' 040
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 19/11/2025Are you interested in how different AI methods can be used in the treatment of eating disorders and obesity? Come to the symposium of me, @emmadeschuyteneer.bsky.social, and Chunzhuo Wang at #TIPS2025! 131
Reposted by Nicolas LeenaertsTim Kaiser @tkaiser.science · 11/11/2025🚀 New paper (open access) out in Cognitive Therapy & Research: we (@herzog.bsky.social, @evalottabrakemeier.bsky.social, @hudsongolino.bsky.social and me) ask whether group‑level symptom‑change networks in CBT actually capture what happens inside each patient. #Psychology #CBTlink.springer.comMust We Always Go Idiographic? - Cognitive Therapy and ResearchPurpose While psychological change processes are increasingly assumed to be “non-ergodic”, prompting a shift toward idiographic approaches, the assumption of ergodicity is often accepted a priori rath... 54320
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 14/11/2025Everytime I start reading something about Tranformers for timeseries forecasting, I hope for a split second that it's going to be about Optimus Prime trying to predict stock prices. Alas... 030
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 09/11/2025One of the reasons Mr.Beast supposedly chose Saudi-Arabia for his amusement park is because it is in the middle of the world. Can somebody explain to him how earth is a globe... 🌍 000
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 23/10/2025One of the downsides of having some years of experience in academia is seeing how hype-driven research is... 100
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 22/10/2025I really love the 'Deep Learning with Python' book by Francois Chollet and Matthew Watson. For folks that don't know yet, you can read the entire book for free online! Really easy to actually use the code from the exercises. deeplearningwithpython.iodeeplearningwithpython.ioDeep Learning with Python, Third EditionDeep Learning with Python is written for anyone who wishes to explore deep learning from scratch. This new edition adds comprehensive coverage of generative AI and modern deep learning frameworks. It ... 050
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 17/10/2025Wow, coming from a country where there is a ban on making ads for prescription meds, this just shocked me. Serena Williams, a huge celebrity, making an ad for a weight loss product, at a time when so many people are insecure about their weight. Honestly, that just makes me sad. 010
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 16/10/2025After years of careful study, I am proud to say that my research finds that Conchiglie are the best type of #pasta. The way they hold the sauce, Mamma Mia 🤌 I dare other researchers to contradict my findings, but let's be honest.... 010
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 03/10/2025“You’ll never get the award,” said my imposter syndrome. Well, look at me now! Many thanks to the Royal Academy of Medicine for awarding the Prof. Dr. Bernard Sabbe Award in Clinical Psychiatry to my PhD thesis. Read my thesis here: doi.org/10.13140/RG.... 040
Reposted by Nicolas LeenaertsBenjamin Kunc @benjaminkunc.bsky.social · 29/09/2025Are you an ESM item measuring the quality of social experiences looking for validation? 👀 Because if you are, I've got some bad news for you. Our new preprint is out: osf.io/preprints/ps... @gudruneisele.bsky.social @ginettelafit.bsky.social @lisapeeters.bsky.social @oliviajkirtley.bsky.socialosf.ioOSF 265
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 25/09/2025Want a taste of Flemish culture? A mayor secretly used municipal facilities to meet his girlfriend without paying the rental fee. A deontological commission ruled he can stay in office, but he must pay the rent owed. vrtnws.be/p.Bl8P0Nao3vrtnws.beBurgemeester van Zulte moet 3.525 euro huurgeld betalen omdat hij gemeentelijke zalen gebruikte voor afspraakjes met vriendin | VRT NWS: nieuwsDe burgemeester van Zulte, Simon Lagrange (Open Zulte), moet 3.525 euro betalen, omdat hij bijna 50 keer stiekem de gemeentelijke zalen gebruikte voor afspraakjes met zijn nieuwe vriendin. Maar ze bet... 010
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 21/09/2025What’s a psychiatrist doing in computer science? It’s a question I keep getting in the U.S. Luckily, the answer is clear to me: AI holds enormous potential for mental health, but it’s up to us, as clinicians, to guide it in the right direction. Read more in my latest blog post!nicolasleenaerts.github.ioWhat’s a psychiatrist doing in computer science? - EnglishAt yet another welcome event at Harvard, I get ready to repeat my introduction again. In short: I am a psychiatrist from Belgium, and I will be working for a year as a postdoctoral researcher in compu... 010
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 20/09/2025It is imperative that all students working with me watch a compilation of funny vine video's. Otherwise you won't understand my memes 😭 010
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 12/09/2025Final paper of my PhD got published! 🥳 We investigated whether stress increases the desire for immediately available food or alcohol in patients with bulimia nervosa or alcohol use disorder. Check it out here: www.cambridge.org/core/journal...cambridge.orgThe effect of stress on delay discounting in female patients with early-onset bulimia nervosa and alcohol use disorder: functional magnetic resonance imaging study | BJPsych Open | Cambridge CoreThe effect of stress on delay discounting in female patients with early-onset bulimia nervosa and alcohol use disorder: functional magnetic resonance imaging study - Volume 11 Issue 5 0102
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 08/09/2025I love reinforcement learning, but the most annoying part about reading RL papers is the variety in nomenclature and how some authors seem to go out of their way to use specific terms and symbols in their papers... Oh and everybody needs to give a new fancy name to their algorithm... 000
Reposted by Nicolas LeenaertsAaron Fisher @aaronjfisher.bsky.social · 02/09/2025Paper accepted today in the Journal of Psychopathology and Clinical Science, "Establishing minimally sufficient conditions reduces the complexity of symptom presentations in DSM internalizing disorders." A quick thread, below. (link is to a PDF on the paper's OSF page) 1/15 osf.io/fxdm6osf.ioOSF 23914
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 29/08/2025Never thought I'd be working with Lagrangian multipliers, but here I am! 000
Nicolas Leenaerts @nicolasleenaerts.bsky.social · 24/08/2025I have fully embraced being over thirty. There was a fresh salmon promo in the grocery store and I was ecstatic ☺️. 010
Reposted by Nicolas LeenaertsSociety for Ambulatory Assessment 2026 Conference @saa2026.bsky.social · 22/08/2025#SAA2026 key dates: 📭 abstract submissions will open 1 December 2025 and close 16 January 2026 📨 acceptance notifications will be sent at the end of March 2026 - registration will open at the same time 🦜 early bird registration will close at the end of April 2026 univie.eventsair.com/saa2026/ 0105