Unhappy Truth about SAD: It Doesn't Exist, Study Says

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Though many advances have been made in the medical field with regard to psychiatry, still many mysteries exist and much of the human mind remains an unknown. Some mental-disorder diagnoses are clear-cut, whereas others are somewhat of a stretch. Given this, researchers at Auburn University decided to question the validity of seasonal affective disorder as a psychiatric diagnosis.

SAD is a mood disorder that has been part of the Diagnostic and Statistical Manual of Mental Disorders (DSM) since 1987. As its name suggests, it strikes during particular times of the year, the most prevalent form being winter depression. If left untreated, symptoms remit in the ensuing spring or summer. It is not a separate entity, but a subtype of major depressive disorder, or MDD, or bipolar I/II disorder.

In a paper published in Clinical Psychological Science, study authors examined data from 34,294 participants who took part in a large-scale cross-sectional survey of American adults in 2006 as part of the Behavioral Risk Factor Surveillance System (BRFSS), which was a phone-based survey conducted annually. The aim was to determine whether a seasonally-related pattern of occurrence of major depression would emerge based on data from BRFSS.

The survey utilized the Patient Health Questionnaire-8 (PHQ-8) Depression Scale, which has been validated in previous research as a reliable measure of depression in accordance with the DSM criteria. This survey asked participants how many days of the past two weeks had they experienced depressive symptoms. These include:

  • depressed mood
  • loss of interest/pleasure in most or all activities
  • insomnia/hypersomnia
  • change in appetite or weight
  • restlessness
  • low energy
  • poor concentration
  • thoughts of worthlessness or guilt
  • recurrent thoughts about death or suicide

The data revealed that depression was unrelated to latitude, season and sunlight, and thus do not support the validity of a seasonal modifier in major depression (the notion of SAD has more to do with folk psychology than objective data).

SAD has been thought to be a valid clinical syndrome based upon the following: expert opinion that it is a distinct concept, characteristics of the illness are unique, has predictive validity (can reliably predict course of illness and response to treatment) and has construct validity (defining characteristics and pathophysiology are known).

There are several issues with those qualifiers, one of which is epidemiological studies to determine prevalence rely on self-reported questionnaires, which is not rigorous enough of a method to reliably say that a person does or does not have SAD. With regard to the pathophysiology of the disease, it is unknown, and based on potential etiologies involving possible disturbances in Circadian rhythms, decreased sensitivity of the retina, genetic factors, and dysregulation of neurotransmitters such as serotonin. While they do sound fascinating, none of them can reliably be proven nor disproven.

Out of the total population of participants surveyed, 1,754 of them scored within the clinical range of depression and the researchers were unable to observe any seasonal differences in their symptoms. That led the study authors to argue, being depressed during winter is not evidence that one is depressed because of winter.

Oftentimes we buy into ideas because they seem to make sense. Winter is depressing, it s cold and miserable and the days are short. It is understandable why people would dislike it as a season. In an earlier article, the myth that suicide rates go up during the holidays has been very well and clearly debunked.

It is just as important to know what a person is not suffering from as it is to know what they are suffering from because for every misdiagnosis or perpetuated myth, we run the risk of delaying necessary treatment or prescribing inappropriate treatment.