A reader asks:

About five days ago, I increased the amount of time in front of my light box from 30 to 45 minutes, to try to stave off the mid-afternoon slump. It is working more or less, but I think I am now experiencing what you termed “irritable hypomania.” I am definitely more irritable, and I spend much of the day feeling like I am in overdrive. Any suggestions?

Answer:

Yes, you are experiencing morning-light overdose, and should immediately fall back to 30 minutes. An alternate tactic to avoid afternoon slumping is a relatively short supplementary exposure — usually, 10 minutes is sufficient — just as you begin to feel the slump set in. You need not schedule this p.m. exposure precisely (as is important for morning light). Rather, use it when you feel you need it. If you are at work, without your light box, consider getting the new work station lamp (DaylightXL) described at www.sphereone.com. It is relatively inexpensive, but does this kind of job well