Reversed diurnal variation in depression: associations with a differential antidepressant response, tryptophan: large neutral amino acid ratio and serotonin transporter polymorphisms.

Author(s): Joyce PR, Porter RJ, Mulder RT, Luty SE, McKenzie JM, Miller AL, Kennedy MA

Affiliation(s): Department of Psychological Medicine, Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand. peter.joyce@chmeds.ac.nz

Publication date & source: 2005-04, Psychol Med., 35(4):511-7.

Publication type: Clinical Trial; Randomized Controlled Trial

BACKGROUND: Although diurnal variation of mood is a widely recognized symptom of depression, the clinical, neurobiological and psychopharmacological significance of this symptom has not previously been reported. METHOD: A total of 195 depressed out-patients underwent a detailed clinical and neurobiological assessment, and were then randomized to treatment with either fluoxetine or nortriptyline. RESULTS: Of the 195 depressed patients, 62 had a pattern of reversed diurnal variation (i.e. worse in the evening). Those with reversed diurnal variation had a poorer response to a serotonergic anti-depressant, were less likely to have bipolar II disorder, had a higher tryptophan: large neutral amino acid ratio and had different allele frequencies of the polymorphisms in the promoter region of the serotonin transporter. CONCLUSIONS: These findings raise the possibility of serotonergic influence on diurnal variation, and that the symptom of reversed diurnal variation is of relevance to antidepressant prescribing.