Johannes Lieslehto was treating a patient in Helsinki who had cycled through multiple medications for bipolar disorder—lithium, antipsychotics, mood stabilizers—yet kept returning to the hospital during manic episodes. That patient, like so many others, responded poorly to lithium, the long-standing gold standard, and struggled with side effects that made adherence nearly impossible. It was this real-world frustration that sparked a groundbreaking study spanning two countries and over 160,000 lives. At the Karolinska Institute in Stockholm and Niuvanniemi Hospital in Finland, Lieslehto and his team set out to answer a critical question: when lithium fails, what actually works?
Bipolar disorder affects up to 3% of people globally, marked by intense mood swings between mania and depression. While psychotherapy and lifestyle changes help, medication remains the cornerstone of long-term stability. For decades, lithium has dominated treatment guidelines. But in practice, many patients either don’t respond or can’t tolerate it. Until now, high-quality evidence on what to use instead has been scarce. This new study, published in Nature Mental Health, fills that gap with one of the most comprehensive real-world analyses to date.
The researchers analyzed health records from 161,801 individuals diagnosed with bipolar disorder across Sweden and Finland, tracking their treatment courses and psychiatric hospitalizations over several years. What set this study apart was its innovative method: instead of comparing different people on different drugs, they compared each person to themselves over time. This self-matched design minimized bias from genetics, trauma history, or illness severity—factors that often skew results in large studies. By focusing on hospitalizations as a marker of relapse, they could directly measure which treatments kept people stable.
The findings offer clear direction. Patients on clozapine, particularly those receiving it as a long-acting injectable, had the lowest risk of hospitalization. Other effective combinations included quetiapine with lamotrigine and olanzapine with valproate—both linked to significantly fewer relapses after lithium discontinuation. Long-acting injectable antipsychotics emerged as a powerful tool, likely because they ensure consistent dosing, a major challenge in bipolar care. These aren’t just incremental improvements; for clinicians and patients, they represent actionable alternatives backed by robust data.
While the study is observational and can’t prove causation, its scale and design make the results impossible to ignore. For the millions who don’t benefit from lithium, this research offers more than hope—it offers a roadmap. As Lieslehto puts it, “There are viable alternatives when lithium is not sufficient or cannot be used.” With mental health systems worldwide under strain, evidence-based strategies that prevent hospitalization are not just clinically valuable—they’re essential.