SAD – or Seasonal Affective Disorder is a full-blown, debilitating mood disorder, but it is predictable for half the year, at the same time of the year.

If you start feeling lethargic during the fall, have trouble waking up and getting out of bed, start wanting heavy or carb-rich foods, it’s a sign that winter doldrums may be setting in. The mood disorder itself usually sets in weeks later – with chronic low mood, inability to do work, loss of pleasure in usual activities, etc. – and is worst in January and February. Usually, everything is fine again by early May.

The millions of people suffering from full-blown, clinical SAD are just the tip of the iceberg. Somewhere toward the bottom are people who are just dragging, not getting their work done, and generally feeling unhappy. These people may be more inclined to say that the wintertime fatigue is more prominent than a change in mood. Carbohydrate cravings are also common.

The time course is the same, though, usually starting in mid- to late fall and resolving by early May. Importantly, people may experience the blues some years, and full Seasonal Affective Disorder other years. This may be due to differences in the weather pattern, but also to current life stresses. If you’re having trouble with employment or family, it’s more likely you’ll develop a major mood disorder that year.