The prevalence of seasonal affective disorder (SAD) in The Netherlands

Abstract

Since the description of SAD the prevalence of this disorder has been of particular interest. The more so, because early studies, indicated the correctness of the on theoretical grounds - expected interaction between latitude and prevalence rate of SAD. More eleborate prevalence studies, mainly in the USA indeed showed a positive correlation between prevalence rate and latitude. In Europe, only few studies have appeared. Although the results of most of these studies are preliminary and research-methods and criteria vary across studies, tentative conclusions are that the prevalence rates in Europe are considerably lower than in the USA, but that there is a similar trend in the direction of an increase of prevalence at higher latitudes.8"10 In the present study, the prevalence of SAD in the Netherlands is investigated.

Commuter cycling: effect on physical performance in untrained men and women in Flanders: minimum dose to improve indexes of fitness

“…The baseline tests (T1) were conducted between April and June, which makes that the second series of tests (T2) were conducted in the autumn and the beginning of the winter (October–December). This period of the year is characterised by rain and cold weather and seasonal changes in mood and behavior, a phenomenon also experienced across the healthy population (Mersch et al, 1999). The season could have had an impact on the results of the maximal exercise test, especially in the CG.…”

An overview of epidemiological studies on seasonal affective disorder

“…There are at least 6 reliability studies (97±102) and 12 validity studies ( (12,21,77,93). There are at least 6 reliability studies (97±102) and 12 validity studies ( (12,21,77,93).…”

“…Most studies include an SS of 11 or greater as one of the criteria for SAD, thus 11 seems to be the standard (14,15,18,19,21,23,77,78,85,86,90,93,94,106). Most studies include an SS of 11 or greater as one of the criteria for SAD, thus 11 seems to be the standard (14,15,18,19,21,23,77,78,85,86,90,93,94,106).…”

“…9, 12, 14, 15, 21, 77, 93, 96±98, 103, 104, 105) on the SPAQ, both in normal people and in patient populations. There are two main types of validation studies of the SPAQ: ®rst, studies that have found signi®cantly different mean depression ratings scores (or SPAQ scores) between groups of SAD patients and normal individuals(9,14,15,93,97,98); and secondly, studies that compare SPAQ diagnoses with clinical diagnoses of SAD(12,21,77,93,104,105). The test±retest correlation for the SS scale ranges from 0.65 to 0.87 in different studies.…”

An overview of epidemiological studies on seasonal affective disorder

“…There are at least 6 reliability studies (97±102) and 12 validity studies ( (102). There are two main types of validation studies of the SPAQ: ®rst, studies that have found signi®cantly different mean depression ratings scores (or SPAQ scores) between groups of SAD patients and normal individuals (9,14,15,93,97,98); and secondly, studies that compare SPAQ diagnoses with clinical diagnoses of SAD (12,21,77,93,104,105). One study found excellent agreement (77) while the others found only moderate agreement.…”