Conditions: Depression Major Depressive Disorder Unipolar Depression
Keywords: depression serotonin norepinephrine SSRI Wellbutrin bupropion executive function residual symptoms
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 32
Healthy volunteers: no

Brief summary:
Many people with depression are treated with a serotonin-specific reuptake inhibitor anti-depressant (SSRI) and feel 'better'. Although many people feel 'better', they do not feel completely 'well'. Often, individuals continue to complain of cognitive problems such as lack of attention, diminished motivation, and impaired problem-solving. This study looks at whether residual and cognitive symptoms of depression in individuals are affected by the addition of Wellbutrin (bupropion).

Detailed description:
As many as 65-75% of treated patients continue to experience residual symptoms of depression. Cognitive impairments feature frontal cognitive dysfunction. Many experts believe that executive functions are better predictors of functional level than psychiatric diagnoses.

Frontal cognitive impairment and changes in neuroimaging are seen in individuals depleted of tryptophan, a serotonin precursor. These cognitive changes do not improve following serotonin-specific reuptake inhibitor treatment and at least one study has found that executive dysfunction predicts non-response to fluoxetine. In many patients, remission of mood symptoms in depression requires medications to target non-serotonergic neurotransmitter systems. Brain areas mediating executive functions receive rich noradrenergic inputs, and norepinephrine is known to be intimately involved in many of the executive functions.

A better understanding of serotonergic and catecholaminergic interactions would enable evidence-based treatment of depression which maximizes executive cognitive functions. This study examines the hypothesis that individuals treated with Wellbutrin will have higher scores on tests of executive functions and lower scores on depression indices.

Arms:
arm 1: Subjects randomly assigned to the Wellbutrin then Placebo group will receive 100mg BID of Wellbutrin at the first visit following intake (Week 0).Subjects will be increased to 150mg Wellbutrin BID at Week 1 unless moderate/severe side effects are reported. If subject and rater classify 1+ symptom as severe or 2+ symptoms as moderate, subject will continue on 100mg of bupropion qAM. If subject and rater classify 1+ symptom as moderate or 2+ mild as moderate, subject will continue on Wellbutrin 100mg BID. At Week 4, subjects will cross-over to placebo and will continue to take placebo until Week 8. arm 2: Subjects randomly assigned to the Placebo then Wellbutrin group will receive placebo until Week 4 when they will cross-over to active drug. At Week 4, subjects will be assigned 100mg Wellbutrin BID. At Week 5, Subjects will be increased to 150mg Wellbutrin BID unless moderate/severe side effects are reported. If subject and rater classify 1+ symptom as severe or 2+ symptoms as moderate, subject will continue on 100mg of Wellbutrin qAM. If subject and rater classify 1+ symptom as moderate or 2+ mild as moderate, subject will continue on bupropion 100mg BID. Subject will continue on the assigned dosage until Week 8 of study.

Interventions: intervention 1: Wellbutrin intervention 2: Placebo
Intervention descriptions: intervention 1: None intervention 2: None

Protocol document: