Brain-based explanations of addiction have become a prominent explanatory model in recent decades. Although opposing views have been published, there is no large-scale study of researchers' opinions, unlike for treatment staff, the public and affected individuals. Therefore, this study aimed to examine international addiction researchers' perspectives on: (i) brain-based explanations of addiction; (ii) the perceived dominance of the concept in science, society, treatment and among those affected; and (iii) researchers' general conception of addiction in terms of ontologies and causes. A sample of 1440 international addiction researchers was compiled. Views were assessed online via LimeSurvey using a 'mixed methods light' approach (Likert-type scales, free-text fields). Qualitative content analyses of free-text comments complemented descriptive statistics. One hundred and ninety researchers participated (13.19% response). The classification of substance use disorders as brain diseases/disorders was shared by about 60% of the respondents. Approximately 80% considered it the dominant view in science, but fewer in treatment, society and affected persons. Approximately 75% found it an oversimplification, but regarded it as helpful for understanding substance use disorders. Altogether, various biological, psychological and social factors were considered causal. Comments indicated that an over-simplistic nature of brain-based explanations of addiction was viewed as particularly problematic. A rejection of a simplistic view of addiction in favour of a multi-causal concept in which the brain plays a role seems to be the majority view of participating researchers. Therefore, the orientation of future research, treatment and support for addicted persons need to be reconsidered accordingly.