After 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!

Loved 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

Had 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.

Abstract 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!

The 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...

When you submit a bunch of jobs to the compute cluster...

The 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/overview

Picture 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!

Meta-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.

Saw 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

Have 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...

Found where he lives!

If 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...

As 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 😵

Really interesting paper for everybody dealing with missing data.

Watch 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...

I'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!

Harvard in the snow... Oh and I'm also in the picture.

Analysis 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!

After 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...

Snapshots from our symposium at #TIPS2025 where I, @emmadeschuyteneer.bsky.social, and Chunzhuo Wang presented our work on using #AI to treat #eatingdisorders and #obesity.

Want 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.

Here @mcleanhospital.bsky.social with Tori Votaw to give a presentation on using reinforcement learning to improve JITAIs for cannabis use!

We used LLM's to {insert topic here}.

Join us in Vienna next year for #SAA2026. Abstract submissions are now open: univie.eventsair.com/saa2026/subm...

‘It being Monday’ is showing up as the strongest predictor for a negative outcome in my dataset. Who am I modeling? Garfield? 🐈

Got selected as a MAPCI 2026 fellow! Really excited to learn how to develop JITAIs for cancer survivors struggling with substance use!

Only 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

Our 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/

Surely we can all agree that having Black Friday deals for GLP-1 agonists is just not OK.

I 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.'

Are 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!

🚀 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 #CBT

Everytime 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...

One 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... 🌍

One of the downsides of having some years of experience in academia is seeing how hype-driven research is...

I 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.io

Wow, 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.

After 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....

​“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....

Are 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.social

Want 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.Bl8P0Nao3

What’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!

It is imperative that all students working with me watch a compilation of funny vine video's. Otherwise you won't understand my memes 😭

Final 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...

I 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...

Paper 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/fxdm6

Never thought I'd be working with Lagrangian multipliers, but here I am!

I have fully embraced being over thirty. There was a fresh salmon promo in the grocery store and I was ecstatic ☺️.

#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/