To The Editor: In their article published in the November 2007 issue of the Journal, Brianna Sullivan, B.A., and Tabitha W. Payne, Ph.D., used the Seasonal Pattern Assessment Questionnaire to establish a diagnosis of seasonal affective disorder (1). We would like to highlight several important methodological aspects related to the Seasonal Pattern Assessment Questionnaire. First, the questionnaire is not sensitive enough to be considered a diagnostic instrument for determining seasonal affective disorder. However, it is accurate enough to be used as a screening instrument (2, 3). Since the authors did not employ any structured clinical assessment, the validity of the Seasonal Pattern Assessment Questionnaire-derived diagnosis of seasonal affective disorder (or seasonal depression) can be questioned. It might be highly possible that although the college students who were diagnosed with seasonal affective disorder experienced seasonal mood changes, the severity of their depression did not warrant a DSM-IV clinical diagnosis of “depression with seasonal pattern.” Our assertion is validated by the mean Beck Depression Inventory–II scores (mean=10.20 [SD=7.75]) reported for the seasonal affective disorder sample and the fact that subjects with major depression were deemed to have a Beck Depression Inventory–II score ≥18. Additionally, high depression scores among the three subjects who had qualifying seasonal affective disorder symptoms (according to Beck Depression Inventory–II criteria) could have skewed the mean score, thereby re-affirming our assertion regarding usage of the Seasonal Pattern Assessment Questionnaire as a diagnostic instrument.
Second, subjects with seasonal affective disorder may not have developed the full clinical symptoms of major depression at the time they were assessed, since the assessment occurred within approximately 4 weeks of the onset of Winter and the end of daylight saving time (October 27, 2003). The Winter period is defined most commonly as the time between November and February (2, 4). It may have been useful if the authors had considered the respondents’ data regarding the following question: “Which month of the year do you feel worst?” There may be a distinct possibility that some individuals who experienced seasonal affective disorder may have reported feeling worse in December, January, or February. This being the case, their Beck Depression Inventory–II scores would understandably be lower than expected as a result of being assessed in November (a month in which their mood was not “worst”).
Last, the Seasonal Pattern Assessment Questionnaire does allow for a diagnosis of subsyndromal seasonal affective disorder, a milder form of seasonal affective disorder (2). Thus, per study design, subjects with subsyndromal seasonal affective disorder were probably classified with the non-depressed group. It would have been useful to examine subsyndromal seasonal affective disorder subjects as a distinct group because the non-depressed group showed a relatively high cognitive failure score. It may be highly possible that there were two distinct subsyndromal seasonal affective disorder groups, i.e., 1) non-depressed subsyndromal seasonal affective disorder (subjects who manifested cognitive failures) and 2) non-depressed, non-subsyndromal seasonal affective disorder (subjects with minimal or no cognitive failures). This approach would intuitively correlate with the authors’ suggestion (1) of more awareness of the effect of seasonal mood changes in college students.
1.Sullivan B, Payne TW: Affective disorders and cognitive failures: a comparison of seasonal and nonseasonal depression. Am J Psychiatry 2007; 164:1663–1667
2.Magnusson A: An overview of epidemiological studies on seasonal affective disorder. Acta Psychiatr Scand 2000; 101:176–184
3.Mersch PP, Vastenburg NC, Meesters Y, Bouhuys AL, Beersma DG, van den Hoofdakker RH, den Boer JA: The reliability and validity of the Seasonal Pattern Assessment Questionnaire: a comparison between patient groups. J Affect Disord 2004; 80: 209–219
4.Eagles J: Seasonal affective disorder. Br J Psychiatry 2003; 182: 174–176
Dr. Gupta is a member of the Seasonal Affective Disorder Association—United Kingdom. Dr. Sharma reports no competing interests.
This letter (doi: 10.1176/appi.ajp.2008.07121904) was accepted for publication in January 2008.