Seasonal Depression And Cognitive Behavioral Therapy: Does It Work?

Have you considered clinical trials for Seasonal affective disorder (SAD)?

We make it easy for you to participate in a clinical trial for Seasonal affective disorder (SAD), and get access to the latest treatments not yet widely available - and be a part of finding a cure.

Seasonal affective disorder

Seasonal affective disorder (SAD) is a common form of depression that follows a seasonal pattern. It affects over 230 million people globally and generally lasts for 40% of the year¹. 

SAD is most commonly experienced during the winter months when you have less sunlight exposure due to the shorter, darker days. 

Symptoms and causes

Symptoms of seasonal depression include low mood, lack of interest in activities you used to enjoy, changes in appetite and sleep, difficulty thinking clearly, and suicidal thoughts. 

SAD most commonly affects those aged between 18 to 30, and it is thought to be caused by a combination of factors. 

Limited sunlight during winter can shift your biological clock (circadian rhythm), causing a biochemical imbalance, which in turn causes you to become out of sync with your daily biological schedule. 

This is because your body relies on sunlight to time certain activities, such as when to wake up, eat, and sleep. Without this, your body struggles to time these important functions. 

Other potential causes of SAD include increased melatonin production, a hormone your body makes when exposed to darkness and causes you to feel sleepy. If you have seasonal depression, your body produces more melatonin.

SAD has also been thought to be driven by lower serotonin levels, a neurotransmitter in the brain that impacts your mood, sleep, and appetite. Exposure to sunlight triggers the release of serotonin, so lower levels of sunlight can lead to depression. 

Risk factors


You can be diagnosed with SAD if you have the symptoms of major depressive disorder. These symptoms must be present during specific seasons for at least two consecutive years. 

Once you are diagnosed, your healthcare provider will give you treatment options, which may include light therapy, medication, talk therapy, or a combination of these treatments. 

Managing symptoms

SAD can vary widely in its severity. You may find you can manage the condition and even resolve your symptoms by taking preventative steps and learning more about the condition. 

Common strategies include exercising, a healthy diet, journaling, establishing a routine, socializing, and getting outdoors

While these are great management tools, it is important to talk to a doctor about your symptoms and start an appropriate treatment program. 

What is CBT?

Cognitive behavioral therapy (CBT) is the most researched treatment for depression, pioneered by Aaron Beck in the 1960s. Beck theorized that “emotional negative thoughts” led to emotional problems. 

The concept behind CBT is that your thoughts, feelings, actions, and physical sensations are interconnected. CBT is a form of talk therapy that helps you manage your emotions by identifying underlying thought patterns and altering how you think and behave. 

What does CBT look like?

There are a few different types of CBT, each with slightly varying approaches. However, all kinds of CBT aim to address the underlying thought patterns contributing to your stressors and emotional concerns. 

This involves working alongside your therapist individually or in groups, typically meeting weekly or fortnightly. 

You can do CBT online, through self-help books, or with a therapist. 

CBT involves steps such as identifying negative thoughts and then problem-solving to find positive alternatives. This is followed by ongoing self-monitoring, which involves tracking behaviors and experiences over time while checking in with your therapist regarding your progress.

The benefits of CBT

CBT has many benefits, such as helping you to acknowledge your underlying thought patterns and harnessing the self-awareness needed to change them. You can learn skills and strategies to better cope with future stressors. 

Another benefit of CBT is that it be administered over a relatively short period — about five to 20 sessions. It is effective² both in-person and online and can be delivered at a relatively low cost. 

Potential challenges

CBT requires you to be willing to change your thoughts and behaviors, as simply being aware of problematic thought processes is not enough. 

CBT is not an overnight process, and it requires patience and open-mindedness to make small steps towards greater change over time.

A critique of CBT is that it emphasizes current thought processes and specific issues instead of addressing significant past events that can contribute to mental health conditions. 

What does the research say?

Compared to another popular therapy, light therapy (LT)³, CBT was found to have about the same time of remission for those with SAD. 

However, evidence shows⁴ that CBT produces better long-term outcomes than light therapy. Light therapy targets chronobiology, which addresses issues with the circadian rhythm contributing to your seasonal pattern of depression. Your circadian rhythm is known as your internal biological clock that helps you control your sleep and wake times.  

Light therapy requires you to sit in front of a lightbox for 30 to 45 minutes each day. While light therapy can be highly beneficial in altering brain physiology, it must be performed daily and reinitiated yearly, so CBT may be a more viable option for the long-term management of SAD. 

Light therapy requires active application, but patients often do not continue treatment in following winters. 

CBT compared to medication

As SAD is correlated with changes in serotonin activity, medications targeting serotonin activity are often prescribed if you have SAD. 

Studies⁵ have found CBT to be as effective as medication for the treatment of SAD, and CBT has been found to reduce the risk of remission even after discontinuing treatment. 

Antidepressant medication works by targeting the amygdala in the brain. The amygdala is responsible for processing information and producing emotional responses, which are memorized as sustained emotional associations. 

Depressed patients have been found to have increased and unregulated amygdala activity. The prefrontal cortex region of the brain is responsible for controlling these emotional reactions via the amygdala. Individuals with depression tend to have deficits⁶ in their prefrontal activity. 

CBT is thought to focus on controlling processing by increasing prefrontal cortex control and decreasing the hyperactive amygdala. These skills promote ongoing emotional regulation. 

Antidepressant medication, meanwhile, targets the amygdala directly, triggering a decrease in its activity to normal baseline levels. However, this does not necessarily result in long-term improvement, as it doesn’t address your lack of control over the emotional processing region of the brain, the amygdala. This means that you are susceptible to external stressors that can trigger further harmful responses. 

Other studies⁷ have identified that combining antidepressant medication with CBT is more effective, as they work relatively independently. Combination treatments may also more rapidly alleviate your symptoms, particularly if you have more severe SAD.  This can then be sustained in the long term through CBT. 

Online CBT

Accessing CBT in-person is not always viable due to travel difficulties, long wait times, and costs. Additionally, many individuals avoid seeing mental health professionals due to the stigma attached to mental illness.

Online CBT provides greater access to this therapy, but there are questions about whether it is as effective as face-to-face CBT.

Preliminary evidence⁸ has found that electronically-delivered CBT is as effective as face-to-face CBT, but the potential risk⁹ of online CBT is that it may not identify patients who are high-risk or in crisis.

Another potential downside is that it may not be tailored to the individual, as online CBT tends to adopt a one-size-fits-all approach. However, some programs are much more individualized.

Overall, online CBT is largely effective and significantly more accessible than face-to-face CBT, making it a viable option for individuals at risk or suffering from the seasonal affective disorder.

The lowdown

Cognitive-behavioral therapy is one of the more effective treatments for seasonal depression. If you are interested in CBT, discuss with your doctor or therapist and determine whether this therapy is offered near you or online.

If you’re experiencing depressive symptoms that are impacting your day-to-day life, make sure to contact your doctor or other support networks for help.

Have you considered clinical trials for Seasonal affective disorder (SAD)?

We make it easy for you to participate in a clinical trial for Seasonal affective disorder (SAD), and get access to the latest treatments not yet widely available - and be a part of finding a cure.

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