I don't think that's entirely fair. There does seem to be something distinct about mental disorders - namely, they are defined by the symptoms.
With physical ailments, symptoms are surface manifestations of an underlying physical cause. For example, fever and fatigue in flu are the result of the influenza virus. Crucially, you can have the physical cause without symptoms (such as in the presymptomatic period), so the two are dissociable. Even where the physical cause is unknown, there's still this symptom-cause distinction.
In the case of mental disorders, they're essentially defined by the symptoms. To have depression is to be depressed. To have anxiety is to be anxious. What would it even mean to have depression without being depressed?
While on some level these are physical in a sense (insofar as they result from brain activity), I don't necessarily think we should think about their cause in the same way as a physical ailment.
More to the point, there's a much more obvious sociocultral element to mental disorders. There's no 'objective' line between being sad and being depressed so while we clearly can and should treat depression, it seems to be very different from other diseases.
None of this is to take away from the real suffering people undergo with these disorders. I just don't think that treating them through a strict biological-pathological lens is as useful as people think it is.
With physical ailments, symptoms are surface manifestations of an underlying physical cause. For example, fever and fatigue in flu are the result of the influenza virus. Crucially, you can have the physical cause without symptoms (such as in the presymptomatic period), so the two are dissociable. Even where the physical cause is unknown, there's still this symptom-cause distinction.
In the case of mental disorders, they're essentially defined by the symptoms. To have depression is to be depressed. To have anxiety is to be anxious. What would it even mean to have depression without being depressed?
While on some level these are physical in a sense (insofar as they result from brain activity), I don't necessarily think we should think about their cause in the same way as a physical ailment.
More to the point, there's a much more obvious sociocultral element to mental disorders. There's no 'objective' line between being sad and being depressed so while we clearly can and should treat depression, it seems to be very different from other diseases.
None of this is to take away from the real suffering people undergo with these disorders. I just don't think that treating them through a strict biological-pathological lens is as useful as people think it is.