How to make a “SAD” diagnosis

“It’s season to be aware of seasonal affective disorder (SAD), but don’t expect to find it in your diagnostic handbook.

Scott Patten, MD, professor of psychiatry and epidemiology at the University of Calgary in Calgary, Alberta, Canada, says that SAD is a memorable term that is “well-established among the general public and, to some extent, within the medical profession.'' It's here to stay.” “However, it is important to emphasize that this is not a diagnosis officially recognized by any major classification.”

Researchers coined the term SAD 40 years ago to describe a pattern of depression that begins in the fall or winter and remits in the spring or summer.

Clinicians diagnose this disorder, although it does not have its exact name.

in Diagnostic and Statistical Manual of Mental Disorders, 5th edition. (DSM-5), this condition is considered a subtype of major depression.

Therefore, the specifier “with seasonal pattern” may apply to patients who meet criteria for recurrent major depressive disorder.

This subtype covers cases in which depressive episodes follow a seasonal pattern for at least two years. Onset usually occurs in the fall or winter, followed by remission in the spring or summer. The reverse pattern is also possible, but less common.

According to the manual, seasonal designators should not be used if a stress factor, such as seasonal unemployment, better explains the pattern. Bipolar disorder may also follow a seasonal pattern.

Researchers estimate SAD Approximately 5% of adults are affected In the US. This diagnosis is more common in women than men and is more common in areas away from the equator.

Is there one characteristic symptom?

DSM-5 highlights the following characteristics of winter depression:

• energy loss
• hypersomnia
• craving for carbohydrates
• overeating
• weight gain

Dr. Kelly Lohan, a researcher at the University of Vermont in Burlington, Vermont, has been studying SAD since the 1990s and believes certain symptoms may be characteristic of the disorder. That's fatigue.

“Personally, I have never met anyone who fully meets the diagnostic criteria for a seasonal pattern and does not have fatigue as one of their symptoms,” Lohan said. “Theoretically, they could exist, but I've talked to hundreds of people with seasonal depression, and even if they actually exist, I've never met them. There is no such thing.”

This is different from non-seasonal depression, where insomnia is a more common sleep problem, Patten said.

Clinicians look for at least five symptoms of depression that cause significant disability or distress for at least two weeks, including widespread sadness, difficulty concentrating, low self-esteem, and loss of interest in hobbies.

But the onset of winter depression can last an average of five months, Lohan says. “Major depression takes a long time to develop.”

Treating subsyndromal cases

Even if you don't meet the criteria for major depression with a seasonal pattern, seasonal changes can affect your energy levels and mood. Some patients have “subsyndromal SAD” and may benefit from treatments developed for SAD, such as bright light therapy, said Paul Desan, M.D., director of the center. said. Winter depression research clinic At Yale University School of Medicine, New Haven, Connecticut.

“Many people come to our clinic because of seasonal changes that don't quite meet the criteria for depression, but they're still seeking help,” Dr. Desan says.

1984 paper Researchers who introduced the term SAD considered artificial bright light as a potential treatment for the condition. Researchers spoke to dozens of patients with “depression that recurs at the same time every year,” and found that bright light seemed to help alleviate symptoms.

Subsequent trials found this approach to be effective. Bright light therapy for non-seasonal depression May increase chance of remissionfound in a recent meta-analysis. Light therapy too may increase effectiveness A randomized trial showed the effectiveness of antidepressants in nonseasonal major depressive disorder.

Other treatments for SAD include cognitive behavioral therapy (CBT) and bupropion XL, which is approved as a preventive drug. Other drugs for major depressive disorder may be used.

Exploration of biomarkers

To better understand SAD and available treatments, Rohan is conducting research such as: Test for potential biomarkers Patients treated with light therapy or CBT. She and her colleagues are looking at differences in circadian phase angles (how well the body's internal clock is adapted to daily life) and post-light pupillary responses (how pupils constrict after the lights go out). . They also measured participants' pupillary reactions and brain activity when they saw words associated with winter and summer, such as “blizzard,” “ice,” “sunshine,” and “picnic.”

Studies have shown that treating patients to remission with CBT reduces the risk of subsequent relapse compared to other treatment approaches, Rohan said. That may be because CBT gives people tools to avoid falling into another depressive episode, she says.

avoid self-diagnosis

Lohan cautions patients against self-diagnosis or treatment.

“Talk to your doctor is a good starting point,” she said. “Just because you can go to Costco and leave with a light box doesn't mean you should.”

Phototherapy can have side effects such as headaches, eye strain and patient nervousness, and determining the right dose can be difficult, Lohan said.

Although Desan's clinic's website provides information about the equipment available for phototherapy for patients looking to try this approach, Desan said clinicians, especially primary care clinicians, They agree that they can play an important role in helping patients. In more serious cases, a mental health professional may be needed.

To begin phototherapy, Desan's clinic typically recommends a four-week trial of 10,000 lux of bright light (about the same brightness as being outdoors on a sunny day) for 30 minutes before 8 a.m. recommended to patients.

Still, Patten says certain other issues may explain why patients suffer during the winter. For example, people may experience financial stress around the holidays or consume excessive amounts of alcohol during the holidays.

“It's important for clinicians to think about it broadly,” Patten says. “It's not necessarily light therapy or drug therapy. It could be focusing on other aspects of what's happening to them in the winter.”

Lohan's research is funded by the National Institute of Mental Health, and she receives royalties for a manual on treating SAD with CBT. Mr. Patten and Mr. Dethan had no relevant financial disclosures.