I'm assuming you mean bipolar disorder, whose acronyms are most commonly BPAD (Bipolar Affective Disorder) or just BP, more often used. As mentioned above BPD is the acronym for Borderline Personality Disorder.

I have bipolar disorder. My experiences in terms of my worst/toughest times of day have really varied, but when I do start having certain times of the day worse than others it is usually consistent for a while. I will say that when I've had such issues, mornings are more often on the low energy/low motivation or slightly depressed end. When afternoons and/or evenings are my issue, mood elevation (euphoric or agitated/mixed) is often my problem. Taking my Seroquel XR seems to help the latter, but I don't take it until 7 pm. Sometimes a normal mood or low"ish" morning slowly escalates. By usually 3 pm I can be quite "up".