- Greater than usual drop in serotonin levels
- Disruptions in melatonin release due to lack of light
- People predisposed to MDD with Seasonal Pattern can have variations of the melanopsin-expressing genes
- Circadian rhythm disruption which leads to depression

Washington State University at Tri-Cities

The 'seasonal pattern' specifier is applied when an individual's symptoms of major depressive disorder consistently appear during a specific time of year, most commonly during the fall or winter. This particular subtype is often referred to colloquially as the 'winter blues'.

Major Depressive Disorder with Seasonal Pattern Specifier

Freberg, Laura. (2016). Discovering Behavioral Neuroscience: An introduction to biological psychology (4th ed). Cengage

Discovering Behavioral Neuroscience

Partonen, T., Lönnqvist, J. Seasonal Affective Disorder. Mol Diag Ther 9, 203–212 (1998). https://doi.org/10.2165/00023210-199809030-00004

Reference for Seasonal Affective Disorder

Though MDD with seasonal pattern is most commonly marked by seasonal changes, these seasonal changes can be broken down into smaller components of climate and weather that affect how patients report depressive symptoms.

Environmental Effects on MDD with Seasonal Pattern

Symptoms tend to appear in late fall or winter and will wane during spring/summer months. In some exceptional cases this will be reversed. Symptoms often begin mild and worsen as months progress. 
- Depression 
- Low energy
- Sleep issues
- Feeling hopeless/worthless
- Suicidal thoughts

Symptoms of MDD with Seasonal Pattern

- Light therapy (patient exposed to bright lights)
- Melatonin supplement
- Antidepressants

Treatments for MDD with Seasonal Pattern

A study investigating the effects of weather, daily sunshine, and daily rainfall on depression and mood to determine if weather conditions were related to seasonal depression

Does the weather make us sad? Meteorological determinants of mood and depression in the general population

Possible Causes of MDD with Seasonal Pattern

Read the following scenario and determine the most appropriate specifier to describe the pattern of the individual's depressive episodes. Justify your answer by referencing specific details from the case.

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