Seasonal affective disorder

Psychology
- Seasonal affective disorder

Seasonal affective disorder (SAD) is a mood disorder subset in which people who typically have normal mental health throughout most of the year exhibit depressive symptoms at the same time each year. It is commonly, though not always, associated with the reductions or increases in total daily sunlight hours that occur during winter or summer.

Common symptoms involve excessive sleep, low energy levels, and overeating. In summer, the condition may lead to increased anxiety. However, the duration, severity, and symptoms of Seasonal Affective Disorder (SAD) vary significantly among individuals. For example, in 20% of patients, the disorder fully dissipates within five to eleven years, while 33-44% of patients may develop non-seasonal major depression.

In the DSM-IV and DSM-5, the classification of this condition has evolved: It is no longer regarded as a distinct mood disorder but is now a specifier (referred to as "with seasonal pattern") for recurrent major depressive disorder, which manifests at a particular time of the year and fully resolves at other times. Initially, experts expressed skepticism about this condition; however, it has since gained recognition as a common disorder.Nevertheless, the legitimacy of Seasonal Affective Disorder (SAD) was challenged by a 2016 analysis from the Centers for Disease Control that found no correlation between depression, seasonality, or sunlight exposure.

In the United States, the percentage of the population affected by SAD ranges from 1.4% of the population in Florida to 9.9% in Alaska.

Signs and symptoms

Seasonal Affective Disorder (SAD) is a form of major depressive disorder. Individuals affected may display symptoms such as feelings of hopelessness and worthlessness, suicidal thoughts, loss of interest in activities, social withdrawal, sleep and appetite issues, difficulty concentrating and making decisions, decreased libido, low energy, or feelings of agitation. In cases of winter SAD, common symptoms include falling asleep earlier or within five minutes at night, oversleeping or struggling to wake up in the morning, nausea, and a tendency to overeat- particularly craving carbohydrates, which can lead to weight gain. While SAD is often linked to winter depression, it's not uncommon to experience lethargy in spring or other seasonal mood variations. Though symptoms can vary from person to person, those with spring and summer depression may be more prone to insomnia, reduced appetite and weight loss, as well as anxiety or agitation, unlike those with winter SAD.

Bipolar disorder

The specifier' with seasonal pattern' applies to bipolar and related disorders, including bipolar I and II disorders. Most individuals with Seasonal Affective Disorder (SAD) experience major depressive disorder, but up to 20% may also have bipolar disorder. Bipolar disorder is defined by cycles of depression and mania or hypomania. Symptoms of depressive episodes include low energy, difficulty concentrating, changes in sleep and appetite, feelings of hopelessness, and suicidal thoughts. Manic episodes, more prevalent in Bipolar I disorder, may involve elevated mood, reduced need for sleep, impulsivity, and increased activity or risky behavior. In contrast, hypomania in bipolar II disorder is characterized by milder mania without significant daily life impairment. It's essential to differentiate diagnoses due to crucial differences in treatment. Individuals with the' with seasonal pattern' specifier may experience depressive episodes due to either major depressive disorder or bipolar disorder during winter, with improvement in summer. Approximately 25% of bipolar disorder patients may exhibit a depressive seasonal pattern, often linked to bipolar II disorder, rapid cycling, eating disorders, and increased depressive episodes. Biological sex influences clinical characteristics related to the seasonal pattern: males tend to show more bipolar II disorder and a higher frequency of depressive episodes, while females exhibit rapid cycling and eating disorders.

ADHD

In 2016, a study by the National Institute of Health revealed that "seasonal and circadian rhythm disturbances are significantly associated with ADHD symptoms." Participants diagnosed with ADHD were found to be three times more likely to exhibit symptoms of Seasonal Affective Disorder (SAD) compared to those without ADHD (9.9% vs 3.3%), and about 2.7 times more likely to experience subsyndromal SAD symptoms (12.5% vs 4.6%). Individuals with both ADHD and SAD often face symptoms such as sluggishness, irritability, and withdrawal. Another study published in the Journal of Affective Disorders indicated that roughly 27% of adults with ADHD also suffer from SAD, with a higher prevalence in women compared to men.

Cause

Many species experience reduced activity in winter due to less available food, decreased sunlight- particularly for diurnal animals- and challenges posed by cold weather. While hibernation is a notable example, even non-hibernating species frequently show behavioral changes during this season.

Numerous proximate causes have been suggested. One potential explanation is that Seasonal Affective Disorder (SAD) is associated with an insufficiency of serotonin, and polymorphisms in the serotonin transporter may influence SAD, despite ongoing debate surrounding this assertion. Mice that are unable to convert serotonin into N-acetylserotonin due to the enzyme serotonin N-acetyltransferase seem to exhibit " depression-like " behaviors. Furthermore, antidepressants such as fluoxetine promote an increase in the activity of serotonin N-acetyltransferase, leading to effects akin to those of antidepressants. An alternative theory posits that the etiology may be linked to melatonin, which is synthesized in low light and darkness by the pineal gland, as there exist direct pathways through the retinohypothalamic tract and the suprachiasmatic nucleus that connect the retina to the pineal gland. The secretion of melatonin is regulated by the endogenous circadian clock but can also be inhibited by exposure to bright light.

A study examined whether certain personality traits could predispose individuals to Seasonal Affective Disorder (SAD). It found that those with SAD often displayed correlations with traits such as increased neuroticism, agreeableness, openness, and an avoidance-oriented coping style.

According to Pfizer, risk factors for SAD consist of being female, being younger, having a prior diagnosis of severe depression or bipolar disorder, possessing a family history of similar conditions, or residing far from the equator.

Management

Treatments for classic (winter-based) seasonal affective disorder include light therapy, medication, ionized-air administration, cognitive-behavioral therapy, and carefully timed supplementation of the hormone melatonin.

Light therapy

Photoperiod-related alterations in the duration of melatonin secretion may affect the seasonal mood cycles of SAD. This suggests that light therapy may be an effective treatment for SAD. Light therapy uses a lightbox that emits far more lumens than a customary incandescent lamp. Bright white "full spectrum" light at 10,000 lux, blue light at a wavelength of 480nm at 2,500 lux, or green (actually cyan or blue-green) light at a wavelength of 500nm at 350 lux are used, with the first-mentioned historically preferred.

Bright light therapy is effective when patients sit at a prescribed distance- typically 30 to 60 cm- in front of the box with their eyes open, although they should not gaze directly at the light source, for a duration of 30 to 60 minutes. A study from May 2010 suggests that the blue light commonly used to treat Seasonal Affective Disorder (SAD) might be better replaced with green or white light. Finding the optimal schedule is crucial. Research reveals that up to 69% of patients consider lightbox treatment inconvenient, and about 19% discontinue usage for this reason.

Dawn simulation has also proven to be effective; some studies indicate an 83% better response compared to other bright light therapies. When compared in a study to negative air ionization, bright light was shown to be 57% effective, while dawn simulation reached 50%. Patients using light therapy may experience improvements during the first week, but increased benefits are typically evident with continued use over several weeks. Certain symptoms, such as hypersomnia, early insomnia, social withdrawal, and anxiety, resolve more rapidly with light therapy than with cognitive behavioral therapy. Most studies suggest it is effective without year-round use, instead recommending it as a seasonal treatment lasting several weeks until frequent light exposure is naturally obtained.

Light therapy may involve exposure to sunlight, achieved by either increasing outdoor time or using a computer-controlled heliostat to direct sunlight into homes or offices. While light therapy is the primary treatment for seasonal affective disorder, it's important to avoid extended exposure to direct sunlight or artificial lights that do not filter out ultraviolet rays, as they can increase the risk of skin cancer.

The evidence base for light therapy as a preventive treatment for seasonal affective disorder is limited. The decision to use light therapy to treat people with a history of winter depression before depressive symptoms begin should be based on a person's preference for treatment.

Medication

SSRI (selective serotonin reuptake inhibitor) antidepressants have proven effective in treating SAD. Effective antidepressants include fluoxetine, sertraline, and paroxetine. Both fluoxetine and light therapy are 67% effective in treating SAD, according to direct head-to-head trials conducted during the 2006 Can-SAD study. Subjects using the light therapy protocol showed earlier clinical improvement, generally within one week of starting the clinical treatment. Bupropion extended-release has been shown to prevent SAD in one in four people, but it has not been compared directly to other preventive options in trials. In a 2021 updated Cochrane review of second-generation antidepressant medications for the treatment of SAD, a definitive conclusion could not be drawn due to a lack of evidence and the need for larger randomized controlled trials.

Modafinil can be an effective and well-tolerated option for those with seasonal affective disorder or winter depression.

Another explanation is that vitamin D levels are too low when people do not receive enough Ultraviolet B exposure on their skin. An alternative to using bright lights is taking vitamin D supplements. However, studies did not show a link between vitamin D levels and depressive symptoms in elderly Chinese, nor among elderly British women who were given only 800 IU when 6,000 IU is needed. 5-HTP (an amino acid that aids in producing serotonin and is often used to help those with depression) has also been suggested as a supplement that may help alleviate the symptoms of SAD by uplifting mood and regulating sleep schedules for those with the condition. However, those taking antidepressants are advised against using 5-HTP, as antidepressant medications may interact with the supplement to create dangerously high levels of serotonin, potentially resulting in serotonin syndrome.

Other treatments

Depending upon the patient, one treatment (e.g., lightbox) may be used in conjunction with another (e.g., medication).

Negative air ionization, which involves releasing charged particles into the sleep environment, has been found effective, with a 47.9% improvement if the negative ions are in sufficient density (quantity).

Physical exercise has proven to be an effective therapy for depression, especially when combined with other treatments for SAD. One study highlighted significant effectiveness in alleviating depressive symptoms by pairing regular exercise with bright light therapy. Patients who engaged in 20-minute sessions on an aerobic bike during the day, along with equivalent time under UV light, experienced rapid recovery.

Among the psychological therapies designed to prevent Seasonal Affective Disorder (SAD), cognitive-behavioral therapy (CBT) has received the most research attention. This therapy often includes using thought records, activity schedules, and positive data logs. However, the evidence supporting CBT or any psychological therapies for preventing SAD is still inconclusive.

Criticism of disorder and diagnosis

The validity of SAD has been questioned multiple times. A 2016 analysis from the Centers for Disease Control found no links between depression, seasonality, or sunlight exposure and suggested discontinuation of the diagnosis. Furthermore, a 2018 study focusing on the instability of SAD diagnosis criteria over prolonged periods indicated that SAD is a temporary expression of a mood disorder rather than a specific disorder.

See also [ Plutchik's Wheel of Emotions ]

Emotions