I treat bipolar + anxiety with a 2-pronged approach. Mood stabilizers for the bipolar and benzodiazepines for the anxiety.

>Mood stabilizers:
>>Lamictal/Lamotrigine(200mg/night) as long-term mood stabilizer.
>>Seroquel/Quetiapine Fumarate (tapering out now that Lamictal has evened my keel)

>Anxiety: I only take Lorazepam now, but have been prescribed various benzos over the years. Here are my completely subjective observations:
>>Xanax/alprazolam (1mg) - great for panic attacks, kicks in fast and hard. Knocks all emotions away. Very tiring though, I'd often oversleep afterward. Stupefying, but sometimes that's what you need. It wears off quickly and I got rebound anxiety. Oh, also xanax muchies!
>>Valium/diazepam (5mg) - Like a gentle pat on the back that says "it'll be okay." More gentle onset and taper. Helped with anxiety when traveling.
>>Ativan/lorazepam (1mg) - for me, the most subtle of the three. Doesn't knock me out too hard, no obvious physical effects. Helps with anxiety, but also agitation.

I started on xanax for a few years. Asked to be switched to valium (much less harsh, xanax rebound anxiety was rough). Later asked to be switched to lorazepam (since these days agitation hits me harder than anxiety when they do show up). None is really better or worse; this progression has more to do with the evolution of my mental health.

Good luck, BP+anxiety can be a pretty wicked combo. All these observations are wholly subjective, but hopefully it'll help you get oriented with possible options. Best wishes. -:- M