1-10 percent of people, including many women of reproductive age, suffer from seasonal affective disorder (SAD), a form of depression that shows up in connection with what time of the year it is. Most women with SAD suffer from what’s called the “winter type.” This means that episodes of depression develop any time from mid-fall to late winter. The person begins to feel better in spring time and still feels fine through summer and into the beginning of fall. SAD with depression in other times of the year, such as summer, is less common but it does happen sometimes. Since pregnancy, especially late pregnancy, can trigger depression, women with SAD have an increased chance of becoming depressed during pregnancy.
When we say that depression develops during a particular season, this means what psychiatrists call an “episode of major depression”, or a “major depressive episode”. This means that you are experiencing at least five of the following nine criteria:
- Depressed mood most of the day, nearly every day, as indicated by either subjective report (feeling sad, empty, or hopeless) or observation by others (appears tearful).
- Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day (as indicated by either subjective account or observation.)
- Significant weight loss when not dieting or weight gain (a change of more than 5 percent of body weight in a month), or decrease or increase in appetite nearly every day.
- Insomnia (difficulty falling asleep or staying asleep) or hypersomnia (excessive sleeping) nearly every day.
- Psychomotor agitation or retardation nearly every day (observable by others).
- Fatigue or loss of energy nearly every day.
- Feelings of worthlessness or excessive or inappropriate guilt (which may be delusional) nearly every day
- Diminished ability to think or concentrate, or indecisiveness, nearly every day (either by your own assessment or as observed by others).
- Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation (thoughts about committing suicide) without a specific plan, or a suicide attempt, or a specific plan for committing suicide
A psychiatrist or clinical psychologist can diagnose SAD during an examination and interview. The process involves checking for the criteria listed above, which come from a psychiatric guideline known as the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-V). You may be given a questionnaire, such as the Hamilton Rating Scale for Depression (HRSD), or you may be tested by way of what is called the Mini-International Neuropsychiatric Interview (M.I.N.I.).
SAD must be distinguished from other mood disorders, such as major depressive disorders. This can be done using the Seasonality Pattern Assessment Questionnaire (SPAQ), which hones in on whether the depression develops at a specific time of the year.
How do episodes of depression affect your pregnancy? Simply put, they reduce your quality of life. They can make it harder for you to succeed in work or school, and also can affect your family life, since a depressed mood decreases your ability to remain connected with your partner and children. SAD also can decrease your threshold for developing depression just before and after delivery (peripartum depression). Indeed, often it is difficult for doctors to tell the difference between peripartum depression and SAD, but this may be sorted out with the SPAQ questionnaire, or simply a thorough history revealing mood changes happening during a certain season going back many years. As for the baby, there is some evidence that any kind of depression in a pregnant woman can cause an irregular heartbeat or hyperactivity in the fetus, and possibly some behavioral problems during childhood, including obesity. Adolescents whose mothers were depressed during pregnancy have an increased risk of becoming depressed themselves and of engaging in criminal acts.
For treatment of SAD, there are antidepressant medications, but actually the main treatment is something called light therapy. While there is a phenomenon called “holiday blues”, in which some people feel depressed around the winter holidays, the main trigger for the winter type of SAD appears to be reduced light, especially in the morning. In Earth’s northern hemisphere, this happens to correspond to the winter holiday season, although in the southern hemisphere the winter is June to September. Consequently, SAD has been observed particularly in cities that are at high latitudes (closer to the poles). During the 1990s and early 2000s, scientists realized that it was not only a lack of light that stimulated depression, but lack of light of certain colors. Blue light, in particular, is powerful as it tells a gland called the pineal gland to stop producing the hormone melatonin, which promotes sleep. Consequently, in light therapy, you use a special lamp that provides you with intense light in the blue range during the morning. Since the screens of computers, phones, tablets, and other devices typically produce a lot of light in this range, it is also important to avoid such screens in the hours before bedtime. In other words, the take home message is that intense, blue light is good in the morning and bad at night. Fortunately, many devices have evening settings for their displays.
Another treatment that is effective against SAD is called cognitive behavioral therapy (CBT), which is particularly useful when combined with light therapy. Both therapies can also be combined with medications. For women who are breastfeeding, CBT and light therapy do not pose any dangers. As for antidepressant medications, there are several drugs available that are considered relatively safe during breastfeeding. Keep in mind that constant waking in order to nurse a baby, particularly a newborn, disrupts the sleep cycle, which further increases the chances of triggering a SAD episode.