How to prevent patients from faking it

There are several motivations behind seeking an ADHD diagnosis, and it's often challenging for physicians to tell the difference between real and fake complaints. Is the patient just a hypochondriac? One could legitimately have a genetic disposition and be sure of his ailment, are his complaints real, or is he fabricating the symptoms just to gain access to medication? Since there is currently no definitive method of identification other than clinical diagnosis based on self-reported symptoms and patient history, it's easy to see why such confusion is widespread. Many studies have been conducted to test the fallible methods of diagnosis. One such study at UCLA suggests that four commonly used diagnostic tests are not readily conclusive. Students were given the tests and told to answer the questions as if they were suffering from ADHD. All the tests lent themselves easily to being falsified and evaluators were unable to clearly distinguish between the falsified and sincere results.
College students seem to have figured out how to work this system to their advantage, and they're especially notorious for feigning illness to open up a steady, legal stream of medication. Students often use their new stimulants as study aides, recreational drugs or even easy profit. These dubious motives beg the question: what can we do to stop misdiagnosis?
If uncertainty in diagnosis can be prevented, these controversial issues will inevitably lessen and patients with legitimate diagnoses will be treated with less skepticism. To this end, it's necessary that the motive of ADHD patients be called into question before the doctor passes over the pills. Since childhood impairments are a critical part of the diagnosis, perhaps a definitive check of family history or an interview with other family members would be beneficial. Requiring opinions of employers and teachers could also be helpful, as they would validate the complaints and lessen the likelihood of drug abuse. Regular psychotherapy could also be useful, as dishonest students would have to create a new life story in order to stay consistent with the results of their testing. The more difficult it is to struggle through the process of diagnosis, the more likely it is that liars will not attempt to break the system.
One also has to wonder if ADHD is worthy of diagnosis at all. Many psychological disorders, such as depression, schizophrenia and borderline personality disorder, share the symptoms assigned to this alleged disorder. Could the symptoms of ADHD actually be the signs of a more general psychiatric ailment? Or, on a more disconcerting note, could physicians be misevaluating normal signs of the human condition as symptoms of a syndrome? What could be misconstrued as an abnormal lack of attention in the classroom could actually be due to lack of interest, not a physiological hindrance to concentration. What seems like a pitiable inability to listen to others could actually be due to arrogance, not psychological distress.
Essentially, this controversial disorder needs to be more fundamentally understood so that misdiagnoses can be kept to a minimum.