Yes light therapy lamps do work at boosting your mood.
I suffer from depression myself and at times my mood will change and I will be in a depressed mood especially when winter comes around or when it's cloudy out.
I then turn on the therapy lamp and after about 30 minutes of sitting in front of the light therapy lamp my mood starts improving.
I wish I had bought my light therapy lamp much sooner than I did because it really has helped improve my mood.
If you're depressed or suffer from SAD in the winter and get more depressed in the winter months or even during cloudy days then using a SAD lamp or light therapy lamp can help.
We all need natural sunlight to help us improve our mood so you should also let sunshine into your house as much as possible because sunshine is much better as natural light is also much better for your health and mood than artificial light.
Also try getting outside in the sunshine as much as possible and avoid staying in the house too long.
When the weather is nice I take my Laptop outside and do my work from there on my patio under the shade.
My productivity really increases and my mood increases when I'm outside more.