Veterinary science has finally caught up with human medicine: You cannot treat the body without addressing the mind.
The line between "medical" and "behavioral" is gone. Because in reality, there is no difference.
Research has shown that many behavioral issues are rooted in neurochemistry. For example, dogs with noise phobias (e.g., thunderstorm fear) often have functional deficits in GABA (gamma-aminobutyric acid) receptors or elevated glutamate activity.
Radiographs revealed severe hip dysplasia. The dog wasn't aggressive; he was in agony and wanted to be left alone. By treating the medical pain (surgery and pain management), the "aggressive" behavior vanished without a single pill for anxiety.