Light therapy and seasonal affective disorder

Bipolar II disorder has the highest prevalence of seasonal affective disorder in early-onset mood disorders: Results from a prospective observational cohort study

BACKGROUND

Many mood disorder patients experience seasonal changes in varying degrees. Studies on seasonality have shown that bipolar disorder has a higher prevalence rate in such patients; however, there is limited research on seasonality in early-onset mood disorder patients. This study estimated the prevalence of seasonality in early-onset mood disorder patients, and examined the association between seasonality and mood disorders.

METHODS

Early-onset mood disorder patients (n = 378; 138 major depressive disorder; 101 bipolar I disorder; 139 bipolar II disorder) of the Mood Disorder Cohort Research Consortium and healthy control subjects (n = 235) were assessed for seasonality with Seasonality Pattern Assessment Questionnaire (SPAQ).

RESULTS

A higher global seasonality score, an overall seasonal impairment score, and the prevalence of seasonal affective disorder (SAD) and subsyndromal SAD showed that mood disorder subjects had higher seasonality than the healthy subjects. The former subject group had a significantly higher mean overall seasonal impairment score than the healthy subjects (p < .001); in particular, bipolar II disorder subjects had the highest prevalence of SAD, and the diagnosis of bipolar II disorder had significantly higher odds ratios for SAD when compared to major depression and bipolar I disorder (p < .05).

CONCLUSIONS

Early-onset mood disorders, especially bipolar II disorder, were associated with high seasonality. A thorough assessment of seasonality in early-onset mood disorders may be warranted for more personalized treatment and proactive prevention of mood episodes.

Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches

Seasonal affective disorder or SAD is a recurrent major depressive disorder with a seasonal pattern usually beginning in fall and continuing into winter months. A subsyndromal type of SAD, or S-SAD, is commonly known as "winter blues." Less often, SAD causes depression in the spring or early summer. Symptoms center on sad mood and low energy. Those most at risk are female, are younger, live far from the equator, and have family histories of depression, bipolar disorder, or SAD. Screening instruments include the Seasonal Pattern Assessment Questionnaire (SPAQ). Typical treatment includes antidepressant medications, light therapy, Vitamin D, and counselling. This paper provides an overview of SAD.