title: A Web-based screening instrument for depression and anxiety disorders in primary care.
abstract: BACKGROUND
  Major depressive disorder (MDD) and anxiety disorders are common and result in considerable suffering and economic loss. People suffering from major depressive disorder and/or anxiety disorders are commonly encountered in the primary care setting. Unfortunately, most people with these disorders remain either untreated or inadequately treated; current data suggest that general practitioners fail to diagnose up to half of cases of major depressive disorder or anxiety. There is a need for screening tools that will help physicians and other professionals in primary care recognize and adequately treat major depressive disorder and anxiety disorders. While the currently-available self-report screening instruments have been demonstrated to be reliable and valid, there remain considerable barriers to their widespread use in primary care.
  
  
  OBJECTIVE
  The purpose of the present study is to report preliminary validation data for a freely-available, brief, Web-based, self-report screener for major depressive disorder and anxiety disorders.
  
  
  METHODS
  The Web-Based Depression and Anxiety Test (WB-DAT) was administered to 193 subjects who presented for assessment and/or treatment in ongoing research projects being conducted at the Mood and Anxiety Program and Clinical Research Department at the Centre for Addiction and Mental Health in Toronto, Ontario, Canada. Subjects completed the Web-based screening instrument and were subsequently interviewed with the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) Axis I Disorders (SCID-I/P). The diagnostic data from the screening instrument were then compared with the data from the individual's SCID-I/P interview. Diagnostic concordance between SCID-I/P diagnoses and the Web-Based Depression and Anxiety Test were assessed using Cohen's kappa, sensitivity, specificity, positive predictive value, negative predictive value, and efficiency.
  
  
  RESULTS
  Agreement ranged from acceptable to good (0.57-0.70) for major depressive disorder, panic disorder with and without agoraphobia (PD+/-AG), social phobia/social anxiety disorder, obsessive compulsive disorder (OCD), generalized anxiety disorder (GAD), and post traumatic stress disorder (PTSD). With the exception of generalized anxiety disorder, the sensitivity (0.71-0.95) and specificity (0.87-0.97) for the major diagnostic categories assessed by the Web-Based Depression and Anxiety Test were good. The sensitivity for generalized anxiety disorder was somewhat lower (0.63) but acceptable. Positive predictive values were good (0.60-0.75) for major depressive disorder, obsessive compulsive disorder, generalized anxiety disorder, and post traumatic stress disorder, and acceptable for panic disorder with and without agoraphobia and for social phobia/social anxiety disorder.
  
  
  CONCLUSIONS
  These preliminary data suggest that the Web-Based Depression and Anxiety Test is reliable for identifying patients with and without major depressive disorder and the anxiety disorders of panic disorder with and without agoraphobia, social phobia/social anxiety disorder, obsessive compulsive disorder, and post traumatic stress disorder. Further research is required in a larger sample in primary care.
mesh_terms: D000293:Adolescent; D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis*; D003863:Depression / Q000175:diagnosis*; D005260:Female; D006801:Humans; D020407:Internet / Q000639:trends*; D008297:Male; D008403:Mass Screening / Q000379:methods*; D011320:Primary Health Care / Q000379:methods* / Q000706:statistics & numerical data