title: Sub-threshold manic symptoms in recurrent major depressive disorder are a marker for poor outcome.
abstract: OBJECTIVE
  A small but significant proportion of patients with major depressive disorder (MDD) report mild manic symptoms which are below the diagnostic threshold for a hypomanic episode.
  
  
  METHODS
  We tested for an association between sub-threshold manic symptoms and clinical outcome in almost 600 patients with recurrent MDD who also had no known family history of bipolar disorder.
  
  
  RESULTS
  9.6% of this large sample had a life-time history of sub-threshold manic symptoms. These patients were significantly more likely to have a history of poor response to antidepressants (OR 2.84; 95% CI 1.23-6.56; P < 0.02) and more likely to have experienced psychosis (OR 2.07; 95% CI 1.05-4.09; P < 0.04). They had also experienced more depressive episodes on average (P = 0.006) and were more likely to have been admitted to hospital (P < 0.03).
  
  
  CONCLUSIONS
  Sub-threshold manic symptoms in patients with recurrent MDD may be a useful clinical marker for poor response to antidepressants and a more morbid long-term clinical course.
authors.affiliation: Department of Psychological Medicine, School of Medicine, Cardiff University, University Hospital of Wales, Cardiff, UK. smithdj3@cardiff.ac.uk
authors.forename: D J
authors.initials: DJ
authors.lastname: Smith
authors.forename: L
authors.initials: L
authors.lastname: Forty
authors.forename: E
authors.initials: E
authors.lastname: Russell
authors.forename: S
authors.initials: S
authors.lastname: Caesar
authors.forename: J
authors.initials: J
authors.lastname: Walters
authors.forename: C
authors.initials: C
authors.lastname: Cooper
authors.forename: I
authors.initials: I
authors.lastname: Jones
authors.forename: L
authors.initials: L
authors.lastname: Jones
authors.forename: N
authors.initials: N
authors.lastname: Craddock
mesh_terms: D000328:Adult; D000368:Aged; D000928:Antidepressive Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D000928:Antidepressive Agents