How Seasonal Affective Disorder is Diagnosed

Table of Contents
View All
Table of Contents

Seasonal affective disorder (SAD) is often incorrectly self-diagnosed. For an accurate seasonal affective disorder diagnosis, a certain set of criteria, set forth in the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5) need to be met. The current DSM-5 terminology for SAD is major depressive disorder with seasonal pattern.

During the diagnosis process, a healthcare provider will conduct a psychiatric interview and may give you a standardized screening. It's important to seek diagnosis with a licensed medical or mental health professional if you think you have seasonal affective disorder.

Getting the correct diagnosis for your mental health condition, and ruling out possible physical conditions that might be contributing, will help you receive the most accurate and effective treatment.

What to Know About Seasonal Affective Disorder (SAD)

Verywell / Danie Drankwalter

Professional Screenings

If you believe you have symptoms of seasonal affective disorder, talk to your primary care healthcare provider. Your healthcare provider will likely ask you some questions to learn more about your health history and symptom profile.

Standardized Screening Tools

The healthcare provider might ask you to fill out a standardized screening tool questionnaire. These are designed and backed by research to identify seasonal affective disorder. Examples of screening tools for SAD include:

Seasonal Pattern Assessment Questionnaire (SPAQ)

This screening tool was developed in 1984 and is still a widely-used tool to screen for seasonal affective disorder. It is self-administered and is freely available to the public. The SPAQ can identify both seasonal affective disorder and subsyndromal seasonal affective disorder.

This tool has been demonstrated to be both reliable and valid. Still, it has been criticized as having low specificity and possibly misclassifying people with nonseasonal depression as having SAD and for overdiagnosing patients with SAD.

Seasonal Health Questionnaire (SHQ)

This screening tool is newer than the SPAQ; it was developed in a 2001 study. It is currently not used as often in practice as the SPAQ. However, research indicates that it has a higher specificity and sensitivity than the SPAQ. More high-quality, recent research needs to be performed on the SHQ if it is to replace the SPAQ in practice.

Structured Clinical Interview

The structured clinical interview (SCID) is regarded as the gold standard for diagnosing mental health conditions. This interview is performed by a mental health professional. It follows the outline set forth by the American Psychiatric Association and the DSM-5 criteria for major depressive disorder with seasonal pattern.

The interviewer aims to ask questions in a nonbiased way, and the interview structure is based on the diagnosis criteria in the DSM-5. However, the SCID is a lengthy, time-consuming process that is not realistic for medical practice. It is largely used in research and may not be very realistic for everyday patient care.

Labs and Tests

There is no physiological measure or lab test that can be used to establish a diagnosis of seasonal affective disorder, A correct diagnosis can only be achieved when a medical professional finds that a person meets the DSM-5 criteria through screening or interview.

However, your healthcare provider may still have you complete blood tests or labs during the seasonal affective disorder diagnosis process. A complete blood count (CBC) and a thyroid panel are commonly ordered, as these can identify medical conditions that could be contributing to feelings of lethargy or depression.

Conditions that often overlap symptoms with seasonal affective disorder include other depressive disorders, bipolar disorder, premenstrual dysphoric disorder, chronic fatigue syndrome, hypothyroidism, and substance use disorders. Screening questionnaires may be used for identifying mental health conditions.

Self Testing

Many people find that their moods are affected by the weather or season. Snow, rain, and increased stress surrounding winter holidays can all impact your moods and emotions. However, these normal fluctuations in mood should not be mistaken for a diagnosable mental health condition.

If you are concerned about your mood fluctuations, and if your engagement in daily life is impacted by your mood, bring this concern to your healthcare provider. Self-testing or self-diagnosis of seasonal affective disorder isn't advised.

Many people who think they have seasonal affective disorder might actually have major depressive disorder without a seasonal pattern. The diagnosis criteria for SAD are specific.

Receiving the correct diagnosis is important, because your healthcare provider can help you find the best treatment, which might include prescription medication, psychotherapy, and lifestyle changes.

Additionally, some SAD-specific treatments, such as light therapy, may worsen symptoms for some people with other conditions. For this reason, it's better to seek professional help rather than self-diagnosing.

Determining Subtypes

According to the DSM-5, there is only one official type of seasonal affective disorder, which is classified as "major depressive disorder with seasonal pattern." However, research has identified a few commonly experienced subtypes of seasonal affective disorder.

Keep in mind that none of these subtypes are officially diagnosable, but your healthcare provider may still take them into consideration as you come up with your treatment plan together.

Subsyndromal Seasonal Affective Disorder

Subsyndromal seasonal affective disorder (S-SAD) is a less severe form of seasonal affective disorder. It is commonly referred to as the "winter blues."

People with S-SAD may not meet all this diagnostic criteria for SAD, yet still feel that their daily life is significantly impacted by their seasonal symptoms. In these cases, a discussion with your healthcare provider may result in a recommendation for one or more treatment methods, such as light therapy, supplementation, therapy, or lifestyle changes.

Fall and Winter Seasonal Affective Disorder

Seasonal affective disorder is most commonly associated with a fall and winter seasonal pattern, due to the reduction in natural light and the possible contribution of lower vitamin D. For people with fall and winter SAD, their symptoms will worsen in the colder winter months, and abate in the spring and summer.

Additional fall and winter seasonal affective disorder symptoms may include:

  • Oversleeping
  • Overeating, including cravings for carbohydrates
  • Weight gain
  • Social withdrawal and isolation

Spring and Summer Seasonal Affective Disorder

It is not as well known, but seasonal affective disorder can also have a spring and summer seasonal pattern. This pattern is more rare, and involves a worsening of symptoms in the warmer months, and symptoms abating in the fall and winter.

The symptom profile for spring and summer SAD is also different, and people with this subtype of SAD may be underdiagnosed as a result. Additional spring and summer seasonal affective disorder symptoms may include:

  • Insomnia
  • Loss of appetite
  • Weight loss
  • Agitation and anxiety
  • Aggression

Lifestyle and Environment Indications

People who live at northern latitudes have been repeatedly shown to be at greater risk of developing seasonal affective disorder. During the winter months, these locations receive fewer hours of sunlight. Based on the theories of SAD's mechanism, this creates a greater risk for developing the condition.

For example, it has been found that in the lower 48 U.S. states, only 1% of people were diagnosed with SAD, compared to 9% of people in Alaska.

This might mean that a healthcare provider in northern latitudes would be more likely to consider a SAD diagnosis. They might also take into account how your lifestyle exposes you to natural sunlight during the diagnosis process.

However, SAD is not limited to the northern latitudes, nor only to people who spend more time inside. People living in all environments and having many lifestyles, including spending extended time outdoors, can still develop SAD.

As such, don't plan on moving or greatly changing your lifestyle if you suspect you might have seasonal affective disorder. Instead, bring your concerns to your healthcare provider for an official diagnosis so that you can develop a treatment plan together.

A Word From Verywell

Seasonal affective disorder affects many people and can be a debilitating mental health condition. It is, however, highly treatable. If you think you might have seasonal affective disorder, or are worried about your mental health, discuss your options with your healthcare provider.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Melrose S. Seasonal affective disorder: An overview of assessment and treatment approaches. Depress Res Treat. 2015;2015:178564. doi:10.1155/2015/178564

  2. Thompson C, Cowan A. The seasonal health questionnaire: a preliminary validation of a new instrument to screen for seasonal affective disorderJournal of Affective Disorders. 2001;64(1):89-98. doi:10.1016/S0165-0327(00)00208-1

  3. Brancaleoni G., Hansen V. Classification of recurrent depression with seasonal pattern: a comparison between two diagnostic instruments. European Psychiatry. 2011;28(supplement 1):p.610. doi:10.1016/S0924-9338(11)72317-3

  4. Brodey B, Purcell SE, Rhea K, et al. Rapid and accurate behavioral health diagnostic screening: initial validation study of a web-based, self-report tool(The sage-sr)J Med Internet Res. 2018;20(3). doi:10.2196/jmir.9428

  5. Kurlansik SL, Ibay AD. Seasonal affective disorder. Am Fam Physician. 86(11)1037-1041.

  6. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Washington D.C.

  7. Melrose S. Seasonal affective disorder: an overview of assessment and treatment approachesDepression Research and Treatment. 2015;2015:1-6. doi:10.1155/2015/178564

  8. National Institute of Mental Health. Seasonal affective disorder.

  9. Sandman N, Merikanto I, Määttänen H, et al. Winter is coming: nightmares and sleep problems during seasonal affective disorderJournal of Sleep Research. 2016;25(5):612-619. doi:10.1111/jsr.12416

By Sarah Bence
Sarah Bence, OTR/L, is an occupational therapist and freelance writer. She specializes in a variety of health topics including mental health, dementia, celiac disease, and endometriosis.