Lay-helper therapy cut distress in Polish migrant workers, Dutch trial finds

Many of the international migrant workers who fill low-paid jobs in the Netherlands live with symptoms of anxiety and depression tied to their work and housing conditions, and most never reach mental-health care [s1]. A randomised controlled trial called RESPOND set out to test whether support delivered remotely, by people who are not clinicians, could narrow that gap for one of the country's largest migrant groups [s1].

The answer, published in PLOS Medicine on 17 August 2026, was yes [s1]. Among Polish migrant workers with elevated distress, a two-step programme of guided self-help followed by remote problem-solving cut combined anxiety and depression scores well below those of people left to usual care [s1].

What the trial tested

RESPOND was a parallel-group, two-arm superiority trial [s1]. Polish-speaking migrant workers aged 18 or older who scored 16 or higher on the Kessler Psychological Distress Scale (K10) were recruited through social media and Polish community spaces between May 2022 and January 2024 [s1]. Everyone first received Psychological First Aid; participants were then assigned 1:1 to care as usual or to stepped care [s1].

The intervention had two steps, both delivered by trained non-professional helpers [s1]. Step one was Doing What Matters in Times of Stress, a guided online self-help programme [s1]. Those whose distress persisted — a K10 score of 16 or more — moved to step two, Problem Management Plus, individual psychological support delivered by videoconference [s1]. In practice, most people who finished the first step still qualified for the second: 85 of 95 assessed, or 89.5% [s1].

In total, 218 participants were randomised, 109 to each arm [s1]. The primary outcome was a composite measure of anxiety and depression, the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS), with the main endpoint set at a two-month follow-up [s1].

What it found

At follow-up, the adjusted mean PHQ-ADS score was 14.8 in the intervention group against 21.3 in the control group [s1]. The between-group difference, adjusted for baseline scores, was -6.52 (95% confidence interval -8.73 to -4.31; p<0.001), a Cohen's d of -0.57 that the authors describe as a moderate effect [s1]. Data at the primary endpoint were available for 94 people in the intervention group and 101 in the control group [s1].

The advantage appeared early and held. After the self-help step alone, the adjusted difference was -5.90 (95% CI -8.12 to -3.69; p<0.001; d -0.56); after the problem-solving step it was -4.87 (95% CI -7.18 to -2.56; p<0.001; d -0.44) [s1]. Eight serious adverse events occurred over the trial — two in the intervention arm and six in the control arm — and none were judged related to the intervention [s1].

Why the model matters

Both components are World Health Organization-developed, low-intensity tools designed to be delivered by non-specialists, the approach known as task-shifting [s1]. The appeal is arithmetic. WHO estimates that about 5.2% of adults worldwide live with depression, with the burden higher in women (6.2%) than men (4.1%), and that roughly 322 million people are affected [s2]. There are nowhere near enough clinicians to reach them, and migrant workers — mobile, often working long hours, frequently outside the reach of the formal system — are among the hardest to serve.

RESPOND's design responds to that reality directly. It was remote, so it did not depend on a clinic visit; it was culturally adapted and delivered in Polish; and it relied on helpers who did not need a mental-health degree [s1]. The stepped structure also rations the scarce resource: everyone starts with the lighter, cheaper self-help tool, and only those who need more move to guided support.

The caveats

The trial's authors are careful about how far the result travels [s1]. Generalisability is limited: most participants were women and most had lived in the Netherlands for several years, so the findings may not extend to newly arrived workers or to men, who made up a minority of the sample [s1]. The follow-up was short — two months after the intervention — so the trial cannot say whether the benefit lasts, and participants were not blinded to their allocation, while outcomes were self-reported [s1].

There is also the matter of who was reached. Recruitment through social media and community spaces captures people already connected enough to enrol; the most isolated workers, who may carry the heaviest burden, are the ones a trial like this struggles to include.

What to watch

The finding that matters for policy is not the effect size alone but the delivery model. If guided self-help and remote problem-solving, run by non-professionals, can move a validated distress score by this much, the same architecture could in principle be pointed at other migrant populations and other languages without waiting for a supply of specialists that does not exist. The open questions are durability beyond two months and whether the approach holds when it is scaled outside a trial's supervision — and whether services can find the isolated workers a study recruited around.

Sources

• Effectiveness of a scalable, remotely delivered stepped-care intervention for psychological distress among Polish migrant workers in the Netherlands: The RESPOND randomised controlled trial — PLOS Medicine, 17 August 2026
• Depressive disorder (depression) — Fact sheet — World Health Organization