Withdrawal from substances is a very uncomfortable physiological as well as psychological process. In the case of many substances (alcohol, benzos), withdrawal can be dangerous and even fatal. Unfortunately, there are some nurses who always believe that a CD patient wants as much medication as they can get, and will refuse or resist providing those medications.
Are there some patients that are really like that? Yes, yes there are.
But in detox, your goal is to stabilize the patient physiologically and keep the patient safe. So regardless of whether you think they are just trying to score, you need to really assess the patient.
Underscoring a patient on purpose is not good because then they may not get a medication that they truly need. But at the same time, overscoring a patient does them no favors. Detox IS in its nature very uncomfortable, and the focus of medication is more to prevent complications than to make patients feel nothing whatsoever physically or mentally. Patients need to realize and learn that difference, instead of relying on medication to replace their coping skills or ease every discomfort.
That is why you need to not only consider what your patient tells you, but what you observe in the patient as well. Observe the patient not just at the assessment, but throughout the day when they don't know you are watching. Also get feedback from your techs and other staff about how the patient is doing. If you get abnormally high vitals, it's a good practice to recheck them...but have your patient sit there for a few minutes before you do so. If you have questions or concerns about a patient's S&Sx, bring them to the doctor's attention: I've heard doctors complain about their patients being undermedicated more times than I can count. Or find a nurse who does understand detox and ask his/her advice.
Also, start reading up on substance abuse and withdrawal so you know exactly what to expect from different substance withdrawals, as well as what medications might be used. CIWA is good to evaluate withdrawal progress, but it is also very broad and leans towards ETOH. Withdrawals vary wildly depending on the substance. Opiate withdrawal often resembles a bad case of the flu, cocaine and amphethamine withdrawals sleep for hours on end, while benzo withdrawals may be an anxious, restless, insomniac nervous wreck...but those S&Sx won't start peaking until a few days after they stopped taking them.
If you know what S&Sx to expect and when based on the substance, then you'll be in a better position to recognize what is "normal" withdrawal and what is a red flag for either complications or malingering.
Use your instincts and judgement, ask questions...and yes, keep assessing because it does get easier with time and practice.