10 percent of SAD cases occur in the summer

Despite its significantly lower incidence, summer-risk SAD is as significant as its winter counterpart. Rather than being prompted by less light, the summer version is typically spurred by high temperatures, strong light, distinct summer time social pressures (appearing in a bathing suit, for example), and pollen. Common treatments include keeping cool and prioritizing sleep.

Roughly 10% of the world has SSAD—SAD’s milder, nonclinical cousin

Subsyndromal affective disorder is diagnosed when someone exhibits two of the nine major criteria for depression (but not more than five) as a result of seasonal changes. While it is milder than primary SAD, SSAD is still significant and impacts millions.

Winter-risk SAD is more likely in regions above 40 degrees latitude north

Using latitude, depression prevalence, and populations of women and those aged 18-30, this map shows the risk of experiencing seasonal affective disorder during the winter. Researchers weighted latitude most (50%) and demographics least (5% each for women and young adults). Overall risk is not a useful predictor of prognosis for an individual.

Antidepressants alone may fail to help an estimated one-third to one-half of depressed patients.

US FDA recently approved the first new schizophrenia drug in decades

Though other antipsychotics block dopamine receptors, a new drug, Cobenfy, influences dopamine levels via a different pathway—it stimulates a pair of specialized receptors in the brain that control the release of a substance called acetylcholine. This alternative approach may help patients avoid serious side effects like weight gain. (Some users may experience a paywall.)

Read Norman Rosenthal’s original 1984 paper describing SAD

The study helped formalize research and diagnosis of seasonal affective disorder, catalyzing the development of therapies (like bright light) and leading to broader adoption of effective treatments. It also helped connect the influence of light and seasons on biological mechanisms in the human body, spurring exploration of circadian rhythms.

SAD uniquely affects people with attention-deficit hyperactivity disorder

Those with ADHD—chronic issues with attention and executive function—are primed for SAD. Many are disproportionately evening chronotypes (more awake in the evening), have a delayed sleep phase, and have low sensitivity to light in the morning. This podcast explores the overlap between these two groups.

1 in 10 US adults are taking medication for depression

A US government report indicates that about 10% of US adults took prescription medication for this disorder in 2023. Women, at 15.3%, were more than twice as likely to take one of these medications than the 7.4% of men.

LSD-like drugs may inspire new antidepressants

LSD and psilocybin have shown promise as antidepressants. Using a virtual library of similar chemical compounds, researchers determined via animal studies that two molecules inspired by LSD have antidepressant effects without any associated hallucinogenic experience. These molecules were found to be 40 times more potent than the common antidepressant fluoxetine, also known as Prozac, with antidepressant effects lasting up to 21 days.

SAD 101 from the folks at NIMH—where the condition was first identified

Norman Rosenthal led the team at the National Institute of Mental Health that first identified and described seasonal affective disorder in 1984. This 101 from NIMH explores the basics of the condition, from who develops it to how it is treated.

See how antidepressants—used by roughly 1 in 10 Americans—were discovered.

Explore this deep dive into how SSRIs work

This 101-style explainer on selective serotonin reuptake inhibitors explains how they work in the brain—complete with classroom-style whiteboard drawings. It covers common SSRIs, why someone might try this medication, and a deeper discussion about potential side effects.

JJ Schildkraut theorized depression is linked to brain chemical imbalances—in 1965

Schildkraut was one of the first to put forward this idea, which stemmed from lab animal research. A decade later, researchers published the first landmark paper on fluoxetine—better known by trade name Prozac—which increases serotonin levels in the brain.

Bright light therapy involves basking in 10,000 lux of light for 30 minutes each morning

Nothing is better than going outside and soaking up real sunlight. However, this is harder in winter, especially in very cold and cloudy regions. SAD lamps are designed to project 10,000 lux—a unit of illuminance, or how much light actually hits a surface (rather than how much is produced, like watts). This video discusses product options and practical considerations.

Tirzepatide: A GLP-1 drug that also acts on separate receptors to promote weight loss

Tirzepatide, like semaglutide, is a GLP-1 drug used in diabetes treatment and for weight loss. Unlike semaglutide, it also acts on glucose-dependent insulinotropic polypeptide receptors, proving a second route to reducing appetite as a means to treat diabetes and promote weight loss.

Psychedelic DMT—part of ayahuasca—shows antidepressant promise in small clinical trial

Proponents say this short-acting psychedelic, formally known as dimethyltryptamine, could be particularly promising for medicinal use because longer-acting psychedelics can sideline someone for hours after a treatment with hallucinations. DMT is the primary psychoactive ingredient in ayahuasca, a psychoactive brew used across various South American cultures for spiritual, social, and medicinal purposes.

SAD disrupts melatonin secretion, producing it longer in the morning

The hormone is secreted from the pineal gland in the brain and is key to the timing of sleep. However, the substance does not generate sleep itself. With seasonal affective disorder, the body misperceives the photoperiod—the time with light—and the cycle of sleeping and waking gets off-phase, leading to issues with circadian rhythms.

How depression affects the brain

Treatment for depression has historically hinged on the theory that the condition was caused by underactive or abnormal neurotransmitters, specifically serotonin and norepinephrine. This four-minute video by Yale Medicine details how these neurotransmitters didn't explain the symptoms of depression but, two other neurotransmitters involved in regulating mood and emotion did. GABA and glutamate, some of the brain's most plentiful neurotransmitters, may possibly be the source of depressive symptoms.

Semaglutides, which belong to a class of drugs called GLP-1s, are prescribed for weight loss in combination with diet and exercise because they trigger the release of the appetite-suppressing hormone incretin.

Australian psychiatrists already prescribe psilocybin and MDMA for depression and PTSD

The country green lighted the treatments for July 1, 2023, onward, with MDMA—ectasy—as a post-traumatic stress disorder treatment, and psilocybin—magic mushrooms—as an option for people with treatment-resistant depression.

DBS effectiveness in treating addiction remains uncertain amid inconsistent results

Critics argue that deep brain stimulation should be considered a last resort and not a scalable solution, given its high costs and trials limited to small samples. However, it has helped some patients manage severe opioid use disorder when conventional methods didn’t work.

GLP-1 helps reduce obesity through a number of mechanisms

Clinical studies show GLP-1 drugs, including semaglutide, promote weight loss through a number of effects. These include reduced appetite, slower emptying of the digestive tract, increased insulin production, and more.

How weight loss drugs could reduce obesity costs

A detailed analysis from finance giant ING finds semaglutide and other weight loss drugs could significantly drive down global costs stemming from heart disease and other health problems associated with obesity. The benefits will vary, depending on each country’s demographics and drug and healthcare costs.

GLP-1 drugs mimic a natural hormone that triggers appetite-suppressing effects

Ozempic, one of the brand names for the drug semaglutide, was originally developed in 2012, to help treat Type 2 diabetes. Among other effects, the drug mimics a naturally produced hormone known as GLP-1, which is released while eating to let our bodies know we are full.

Late-stage clinical trials indicate that a common arthritis drug may be a promising treatment for a leading cause of hair loss.

86 commonly used drugs, including certain antidepressants, painkillers, and immunosuppressants, have different results for men and women, according to recent research.

Peptides like GLP-1 account for 31 of 370 new drugs approved by the US FDA between 2016 and 2023.

One theory claims the retinae of SAD patients may fail to adjust to less light in winter

Most people’s eyes become more sensitive to light in the winter months, but some do not. This failure to adjust causes ripple effects on those individuals’ biological clocks. This Ted-ED video provides a clear, brief, narrative explanation of the condition in six minutes.

GLP-1 drugs are under investigation for treating Alzheimer's, Parkinson's, and drug addiction

Researchers are investigating GLP-1 applications for a variety of chronic conditions. One area of interest stems from how study participants using GLP-1 for diabetes and obesity reported describing less longing for wine and cigarettes while taking the medication—intriguing researchers about using the drugs for addiction applications. The drug, they theorize, could bind to receptors that mediate desire. (Some users may experience a paywall.)

Naltrexone blocks the reward effects of alcohol and opioids

Naltrexone is used to treat alcohol and opioid dependence, blocking opioid receptors in the brain, reducing cravings, and preventing the euphoric effects of alcohol or opioids. It is nonaddictive and works best as part of a comprehensive treatment plan, including counseling or therapy, to support long-term recovery.

Mixed reality technologies may help treat depression

A study led by a team from Stanford University showed that MR can help people with depression by providing pathways to engage in activities such as digital board games and dancing. Participants saw reduced symptoms of depression that made their overall treatment plans more successful.

Women are four times as likely to be diagnosed with seasonal depression

This prevalence trend mirrors the broader incidence of depression among women and is well-documented. Researchers suggest the disparity stems from differences in hormones, social role expectations, coping mechanisms, and more. Men may also present with depression differently, and seek help less.

FDA approved the first ever peanut allergy treatment in January 2020

This new medication, called Palforzia, is designed to stave off severe reactions from accidental peanut exposures with a daily dose that is increased over time under an allergist’s supervision. It’s not a treatment that should be administered during an allergic reaction, however. Epinephrine, usually administered via injection, remains the intervention for severe reactions.

How psilocybin could transform mental health treatment

How magical are magic mushrooms, at least where depression is concerned? Some 24 volunteers participated in a study to evaluate the efficacy of using psilocybin in combination with psychotherapy to treat individuals suffering from depression. While some controversies remain about its use—psilocybin is known to cause psychosis sometimes—some scientists think the benefits outweigh the risks.

The popularity of new weight loss drugs has led to a diabetes treatment shortage

The FDA approved Ozempic to help patients with diabetes, but the popularity of semaglutide as a weight loss drug led doctors to prescribe Ozempic to nondiabetic patients who needed to lose weight. Ozempic became so popular that manufacturers could not keep pace with demand, posing risks for Ozempic-users with diabetes.

Ibogaine is being investigated for treating mental health issues and substance abuse

This compound, which is illegal to use in the US, has had promising results for patients who have tried it in other countries for substance abuse and mental health concerns. This psychoactive substance is not without risks, however; this TED talk points out it's also caused fatal cardiac arrhythmias and shouldn't be taken without medical supervision.

The depression paradox refers to a lack of energy to take action to help alleviate it

Activities like exercise, even at low levels, have been shown to alleviate some of depression's symptoms for some people. However, depression saps energy levels, making it particularly difficult to motivate oneself to take helpful action.

GLP-1s are linked to reduced worker illness and cost savings—a 2026 economic analysis finds the weight-loss drugs are tied to a 17% drop in worker sick leave days.