That's like saying that cognitive psychology is second to behaviorism just because behaviorism can be objectively measured. There's a reason why there are neurological, pyschoanalytic, sociological, Gestalt, behaviorist, evolutionary, functionalist, humamanist, ect. perspectives to pyschology: Because one alone cannot fully explain behavior.
Can psychiatry explain multi-intelligences? Can psychiatry illustrate why people who susbscribe to implicit personality theory are at greater risk of contracting AIDS. Can psychiatry point out GroupThink? Is there are neurotransmitter for mutli-intelligences, implicit personality theory, and GroupThink. If there are, hook me up with a pill so I can prevent the reuptake process for MI, because I'll be one smart mofo then.