Treatment Response of Geriatric Depression

This research study will examine how the brain electrical activity of elderly depressed
patients is related to how quickly and how well they respond to antidepressant medication
treatment. Brain electrical activity will be assessed using electrophysiological tests.
Elderly patients with depression will be treated for 12 weeks with an antidepressant
medication commonly used in clinical practice called escitalopram (Lexapro). Before they
start treatment, patients will be asked questions about their depression to measure how
severe it is. They will also be asked to have their brain electrical activity recorded while
they perform tests on a computer screen. The questions about their depression and the brain
electrical recordings will be repeated regularly during the 12 weeks they will be treated
with antidepressant medication. The researchers are interested to see whether the brain
electrical activity of elderly people with depression before they start the medication can
tell us who amongst them and to what extent will finally improve with treatment with
escitalopram (Lexapro). They will also determine whether patients' brain electrical activity,
during the 12 weeks they will be receiving the medication treatment, will change in any way
and whether this change will be linked with the change in the severity of their depression.
It is hoped that information gained from this study will help the investigators to better
understand the brain processes associated with depression and its successful treatment.

Inclusion Criteria:

- Diagnosis: Major depression, unipolar without psychotic features (by DSM-IV criteria)
-Severity of depression: A 24-Item HDRS above 19 at screening and at baseline -

- Level of Executive Dysfunction: Two strata within each age stratum: Stroop Color-Word
scores - one half of the sample < 26, one of half ≥ 26.

- Capacity to provide informed consent.

Exclusion Criteria:

- High suicide risk, i.e. intent or plan to attempt suicide in near future

- Presence of any current Axis I psychiatric disorder (other than unipolar major
depression or specific phobias) including substance abuse (those with a history of
substance abuse must be abstinent for at least 3 months prior to entry)

- Axis II diagnosis of antisocial personality disorder, mental retardation and pervasive
developmental disorder (DSM-IV)

- History of psychiatric disorders such as psychotic depression, primary psychotic
disorder, or bipolar spectrum disorder (bipolar disorder and hypomania are exclusions)

- Cognition: MMSE scores below 24 or diagnosis of dementia by DSM-IV

- Acute or severe medical illness, i.e., delirium, metastatic cancer, decompensated
cardiac, liver or kidney failure, major surgery, stroke or myocardial infarction
during the three months prior to entry; or drugs known to cause depression, e.g.,
reserpine, alpha-methyl-dopa, steroids, sympathomimetics withdrawal

- Presence of a significant neurological disease such as Parkinson's disease, primary or
secondary seizure disorders, intracranial tumors, severe head trauma;
neurodegenerative diseases i.e. MS

- History of failure to respond to escitalopram (Lexapro) (20mg/day for 6 weeks or
longer) during the current or previous depressive episodes

- History of intolerance to escitalopram (Lexapro) or use of concomitant drugs that may
provide reason to believe that escitalopram is contraindicated. Active treatment with
fluoxetine at the time of screening

- Patients' unwillingness or inability to gradually withdraw all other psychotropic
medications (except for the following: Low and stable doses of opiates and
non-benzodiazepine hypnotics (e.g. zolpidem (5 or 10 mg), zaleplon (5 or 10 mg), or
eszopiclone (1 or 2 mg).Low and stable doses of diazepam and other anxiolytics should
be tapered at screening; inability to tolerate taper is not an exclusion criteria.

- Inability to perform any of the ADLs (MAI: ADL subscale) even with assistance, e.g.
walking with a cane is not an exclusion criterion

- Inability to speak English

- Aphasia