A seasonal mood pattern is low mood that comes back at the same time each year. In most cases it starts in late fall or early winter and lifts in spring. To check, take the same questionnaire through the year and note the date and what else was going on. A pattern in your scores cannot diagnose seasonal affective disorder (SAD) or show what caused the change.
If you are thinking about suicide or self-harm
Thoughts of suicide or self-harm need prompt support, regardless of the total or season.
If you need help now. In the US, Call 988 or text 988. Call 911 if you are in immediate danger. Outside the US, contact your local emergency number or find support in your country.
Is it seasonal depression or a hard month?
The National Institute of Mental Health describes seasonal affective disorder, or SAD, as depression with a recurrent seasonal pattern. Most cases follow the winter pattern. Summer-pattern SAD is less common.
For diagnosis, NIMH says depressive episodes must occur in a specific season for at least two years in a row. They must also happen more often in that season than at other times. Not everyone with SAD has symptoms every year.
Do not wait for two full years when you are struggling. The two-year pattern helps with diagnosis. It is not a waiting period for support.
A difficult holiday, work deadline, anniversary, illness, or school term can also return on the calendar. NIMH links SAD to changes in daylight, not the calendar, so holiday stress is not the same thing. That is why dates alone are weak evidence. Track the event and the symptoms separately.
How do winter and summer patterns differ?
Both patterns include depression symptoms. NIMH lists extra symptoms that can come with each form:
| Winter-pattern features | Summer-pattern features |
|---|---|
| Sleeping more | Trouble sleeping |
| Eating more | Poor appetite |
| Carbohydrate cravings | Weight loss |
| Weight gain | Restlessness or agitation |
| Social withdrawal | Anxiety |
This is not a checklist for self-diagnosis. You may have some, all, or none of these features. Medicines, physical illness, stress, pregnancy, substance use, and other mental health conditions can also change sleep, appetite, weight, and energy.
How do I track my mood across the year?
Use the same questionnaire, version, and language each time. The PHQ-9 records depression symptoms over the previous two weeks, and the GAD-7 covers anxiety symptoms over the same period. Neither questionnaire identifies SAD.
Choose a repeat schedule with your doctor or care plan. Each result covers only the two weeks before it. A monthly check leaves gaps, and more frequent checks may overlap. Record the exact date so you know which days each answer describes.
Each time, add a short note on:
- sleep timing and how long you slept
- appetite and energy
- daylight or time outdoors
- work, school, travel, and holidays
- illness and medicine changes
- how you managed day to day
These notes keep details that a total can hide. They also help separate calendar stress from the season and flag other explanations, without claiming that daylight caused anything. Keep them brief, because a usable record beats a detailed one you stop keeping.
What can my scores tell me?
Start with what you observed. For example: “My PHQ-9 totals were higher from November through February in two consecutive years.” That statement stays close to the data.
Then ask what else changed. A winter rise that overlaps with grief, less work, pain, or a medicine change has several possible explanations. So does a summer rise during heat and poor sleep.
A higher total means you reported more symptoms during its recall period. It does not establish SAD, explain why the change happened, or show that one treatment caused a later result.
If retirement changed your routine or social contact, compare the calendar record with the retirement tracking guide. Two patterns can overlap.
Should I try light therapy?
Talk with a doctor before starting light therapy or changing medicine or supplements. NIMH lists light therapy, psychotherapy, antidepressant medicine, and vitamin D among the treatment categories studied for SAD. The right option depends on your pattern, health history, medicines, preferences, and possible risks.
For winter-pattern SAD, NIMH describes a 10,000-lux light box used for about 30 to 45 minutes, usually in the morning. That is a treatment description, not a personal prescription. Some eye conditions and medicines that increase light sensitivity may call for medical supervision or a different treatment.
Bring the product details and your health history to the appointment. A score cannot screen for light-related risks, bipolar disorder, or medicine interactions.
What should I do next?
See a doctor when symptoms last, return, get worse, or interfere with work, relationships, sleep, or self-care. Bring your record, with the questionnaire names, dates, totals, and any answers that worried you. Mark the months when symptoms began and eased.
If you have no record yet, start with one result today. Take the PHQ-9, write down the date and a short note, and repeat it on the schedule you chose. Review the pattern before the season when your symptoms usually change.