A reader asks:

Can children under the age of two suffer from SAD? I have a 20-month-old grandson, and since he has been about three months old, I have been keeping track of his daily moods. When it is cold outside and the shades are drawn–or just a basic cloudy day–there is no living with him. On sunny days, he is totally the opposite. I have expressed my concerns to my daughter. She asked our pediatrician, who says, “He is just a baby.” Should we start keeping a journal?

Answer:

Strictly speaking, one cannot diagnose SAD in a 2-year-old, because winter depression has to have occurred throughout each of the last two years (with summers consistently good), and one cannot reliably assess conventional childhood symptoms of depression at such a young age. Still, your grandson might be weather- or light-sensitive in a way that causes severe behavioral disturbance. The pattern might even be a precursor to SAD. SAD has been treated with light therapy in kids as young as 6 years. Yes, you (or your daughter) should certainly keep a journal, to be able objectively to summarize the pattern as it may continue. Additionally, you might think about placing a dawn simulation system in the baby’s bedroom, with “sunrise” set to the desired morning wake-up time. This is an innocuous, healthful intervention that might override the negative effects of light deprivation. See the apparatus description at the CET Store.