There may have been a miscommunication between you and the resident. Lying and deception are not traits you would necessarily associate with bipolar patients.
True, and that's why this case was difficult at first but....
1-He normally didn't do the motorcycle or cheating thing
2-It went away with lithium
3-the behavior had a cyclical nature consistent with bipolar disorder
His case I couldn't figure out what was going on for the first two months.
You sometimes get other hard-to-tell cases. I mentioned this before but I had a guy that during his cycles would think his wife was cheating on him and that was one of the only symptoms. He didn't meet a DSM-IV criteria for mania, and it was relieved with Lamictal. His symptoms were the paranoia with his wife and becoming easily upset. No other signs or symptoms of mania. Only reason why I even considered medication was because he had this occurring with him every several months, when it happened, it lasted weeks, then it would just go away, and he openly said he didn't know why he had a paranoia she was cheating on him and even pointed to it as irrational. Another factor was he already tried pscyhotherapy for it, for over a year, and he wasn't getting anywhere with it. His psychotherapist, a psychologist I highly respected told me he thought this was an oddball case of bipolar disorder. That also cleared it up.
But if I didn't have the psychology-assistance, I would've spent an extra few weeks to possibly even months frustrated and confused on what to do wtih the case.
I've mentioned this before in other threads. From personal experience, I've seen the DSM-IV work about 95% of the time. You do occasionally get odd-ball cases that don't fit the criteria. A problem with deviating from the DSM-IV (or V) is you get doctors claiming psychiatry is an art and start medicating everything, "I gave her Seroquel because I could tell she was blue and I see Seroquel as a warming medication." (I'm not making that up by the way, another psychiatrist did once tell me that, or more like something along the lines of that because it's not like I wrote down her exact words.)
But not everything fits perfectly within the DSM-IV or V either. If you deviate from the DSM IV or V, I recommend you explain why in detail in your notes, and it be mroe comomon sense and evidenced-based than "she's blue."