In 2011 he was elected a member of the Royal Netherlands Academy of Arts and Sciences,[3] and in 2023, of the Koninklijke Hollandsche Maatschappij der Wetenschappen.
[7] In 2009, van Os proposed the retirement of the diagnosis, schizophrenia, citing its lack of validity and the risk of fundamental attribution error associated with the label.
In its place, van Os proposed a broad and general syndromal definition, more suited to personal diagnosis, which would reduce attribution error.
[12] In 2016 he published an editorial in the BMJ arguing that disease classifications should drop the concept of schizophrenia, as it is an unhelpful description of symptoms.
Since 2020, van Os, together with colleague Prof. Philippe Delespaul, has been working on setting up social trials in the context of mental health service transformation according to the principle of a Mental Health Ecosystem, as described in the book 'We Are Not God', which he wrote together with Myrrhe van Spronsen, and the book 'Kopzorgen: Understanding Psychosis In 33 Questions', which he wrote with Stijn Vanheule.