According to the passage, which of the following may NOT be among the stakeholders of the conference? ( ).

参考解析：

根据第二段The interest in collaborative mental health care is shared by a wide audience, including particularly individuals living with a mental disorder and their families, healthcare professionals from different backgrounds, managers and decision makers, community groups working in the field, physicians (including family physicians, pediatricians and psychiatrists), teachers from academic departments, researchers and collaborators from different sectors (e.g., emergency social services, law enforcement officers, or employers).可知，C研究员和D精神科医生在原文都有提到。B项的surgeon是指外科医生，属于原文healthcare professionals医护人员之一，而A项，心理学家则不属于其中任何一种。故本题正确答案选A。