Sub-threshold manic symptoms in recurrent major depressive disorder are a marker for poor outcome.
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.
Smith
D J
DJ
Department of Psychological Medicine, School of Medicine, Cardiff University, University Hospital of Wales, Cardiff, UK. smithdj3@cardiff.ac.uk
Forty
L
L
Russell
E
E
Caesar
S
S
Walters
J
J
Cooper
C
C
Jones
I
I
Jones
L
L
Craddock
N
N
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
D000928:Antidepressive Agents