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Treatment Resistant Depression: Current Concepts & Treatment Applications
Bradley N. Gaynes, M.D., M.P.H.
Associate Professor
Department of Psychiatry
UNC School of Medicine
Key Questions for Today
What is treatment resistant depression (TRD)?
Why is it important?
What clinical features are associated with TRD?
What is the evidence base for TRD management strategies?
What are the future research directions?
What Is Treatment Resistant Depression?
There is no single accepted definition– It may mean a failure to reduce depressive
severity by at least 50% following treatment– It may mean a failure to reduce absolute
depressive score below a specific cut point– It may mean a failure of symptoms to entirely remit– It may mean failure to respond to one or more
prior antidepressant trials
Why Is Achieving Remission Important?
Residual symptoms put patients at high risk of relapse and recurrence– Patients with residual symptoms after medication
treatment are 3.5 times more likely to relapse compared to those fully recovered (Judd et al, 1998)
– This risk is greater than the risk associated with having ≥ 3 prior depressive episodes
– Similar finding exists after response to cognitive therapy
Fig. 1. Survival analysis of weeks to major depressive episode relapse (MDE): comparing patients with unipolar major depressive disorder who recovered from intake MDE with residual subsyndromal depressive symptoms vs. asymptomatic status.
Wilcoxon Chi Square Test of Difference=47.96; P<0.0001.
Treatment Response Categories
STATE OBJECTIVE CRITERION
CLINICAL STATUS PREVALENCE IN RCTS
Remission HAM-D ≤ 7 No residual psychopathology
~ 40%
Response ≥ 50% decrease in HAM-D without remission
Substantially improved, but with residual sxs
~ 25%
Partial response
25%-50% decrease in HAM-D
Mild-moderate improvement
~ 10%
Nonresponse < 25% decrease
in HAM-D
No clinically meaningful response
~ 25%
When Do You Characterize a Response As Treatment Resistant? After a patient has been on an antidepressant at for
a reasonable amount of time at an adequate dose No commonly accepted time point
– Most drug trial data comes from 8 week long studies– If no onset of response by weeks 4 or 6, there is a 73-
88% chance of not having onset of response by end of 8 wk trial (Nierenberg et al, 2000), so 4 weeks is a reasonable point to increase dose
– An 8-12 week course is consistent with acute treatment framework and allows patients 8 weeks at a dose expected to produce response
When Do You Characterize a Response As Treatment Resistant? No commonly accepted determination of
adequate dose– Range from minimal (e.g., 20 mg fluoxetine) to
moderate dose (e.g., 60 mg fluoxetine)– Most clinicians consider middle range doses
likely “adequate”
A Working Definition of Treatment Resistant Depression
6-8 weeks of at least a middle range dose without remission
What Are the Clinical Features Associated With TRD?
Incorrect primary diagnosis– Is there a primary disorder (e.g., substance-induced
mood disorder) not being treated?– Is there a primary medical condition not being
treated?– Is there an unrecognized depressive subtype?
• Psychotic depression• Bipolar disorder
What Are the Clinical Features Associated With TRD?
Comorbid psychiatric disorders– Anxiety disorders
• Commonly coexist with major depression• Increase the likelihood of more severe depressive symptoms, suicide
attempts, decreased responsiveness, and greater susceptibility to side effects
– Substance abuse – Personality disorders
Depressive severity
Chronicity of depression (illness lasting 2 years or more)
What Are the Clinical Features Associated With TRD?
Patient factors– Compliance– Unusual pharmacokinetics
Physician factors– Underdosing– Inadequate length of treatment
What Evidence Exists to Guide Treatment?
Switching versus Augmentation– Few controlled studies compare the efficacy of these two
options– A review of available literature suggests response rate of
~50% for each– Augmentation is favored by clinicians in patients with
partial response, although partial and non-responders have comparable chances of response
– Adequate trial at optimal dosing a prerequisite to decision
Switching Antidepressants
Limited controlled data to guide decision If side effects led to switch, then use drugs
with different side effect profiles If failure to respond led to switch, consider
switching to a different biochemical profile or to a broader biochemical profile
Switching Antidepressants No clear guide about switching to different class versus same
class– Available clinical trials show benefit with switching to different class,
but within class not yet tested– Open trials label trials show similar benefits – Current recommendations suggest switching classes if 2
antidepressants of same class are ineffective– Are results generalizable?
Recent meta-analysis of clinical trials suggest venlafaxine has quicker onset of action than SSRIs (Thase et al, BMJ, 2001)
RCTs support MAOIs for atypical depression (relative to TCAs)
Augmenting antidepressants: Strategies with Clear Benefit
Lithium: 300 mg bid or tid (blood levels> 0.4 meq/L)– 11 double blind RCTs averaged ~ 50% response
rate– Of the 3 studies involving SSRIs, 2 showed little
benefit– Side effects and monitoring issues remain a
concern to clinicians
Augmenting antidepressants: Strategies with Clear Benefit
Thyroid hormone (T3): 25-50ug/day
– 1 clinical trial and a meta-analysis support benefit
– All published studies involve TCAs and not newer antidepressants
– Side effects: nervousness, insomnia
Strategies With Disputed Benefit Buspirone: 5-15 mg bid
– Open studies showing benefit– 1 clinical trial showing no statistically meaningful
difference (51% vs. 47%) Pindolol (for SSRI): 2.5 mg tid
– Controlled studies suggest acceleration of onset of response
– The 2 controlled studies in TRD patients showed no benefit
Potential Pharmacologic Strategies Untested
Psychostimulants (methylphenidate: 10-40 mg/day)
Atypical antipsychotics Dopaminergic agents Chromium Anticonvulsants
Where Does Psychotherapy Fit In?
Cognitive behavioral therapy has received the greatest amount of study
Other Options
Electroconvulsive Therapy– Response rate in patients with
• inadequate medication trials: 86% • adequate trials: 50%
– Probably treatment of choice for catatonic states
Summary A working definition of TRD:
Failure to remitremit after 6-8 weeks at a middle range dose
Key considerations with TRD– Clarify diagnosis and potential risk factors for persistence– Patient factors: compliance and/or rare pharmacokinetics– Physician factors: underdosing and/or inadequate treatment
length
Summary No clear direction for augmenting vs. switching
– Each appear successful for ~ 50% of patients– If patient tolerating, first try to maximize dose– Four weeks is a critical decision point to modify treatment
When switching antidepressants after one failure, within class or different class choices are reasonable
Available evidence supports lithium and T3 as effective augmenting agents
What We Don’t Know We Have Little Evidence Guiding Treatment Choice After the
First Fails
We Have No Evidence For Those with Two or More Treatment Failures
We Do Not Know Where Psychotherapy Fits In– Reviews suggest that psychotherapy plays a significant role in the
management of treatment resistant depression– We do not know about the benefits of switching to psychotherapy compared to
augmenting medications with psychotherapy
Vast majority of studies excluded patients with common general medical and psychiatric comorbidities
Distribution of IDSC 30 by Setting
0
2
4
6
8
10
12
14
16
18
20
<=15 16-20 21-25 26-30 31-35 36-40 41-45 46-50 51-55 56-60 61-84
IDSC30 Score
Per
cent
PrimarySpecialty
BASELINE: Distribution of HRSD17 by Setting
02468
101214161820
<12 12-14 15-17 18-20 21-23 24-26 27-29 30-32 33-35 36-52
HRSD17 Score
Per
cen
t PrimarySpecialty
Kolmogorov-Smirnov Two-Sample Test Statistic 0.84p-value 0.48
Figure 2
Baseline Suicide Risk: PC vs SC SC patients reported nearly twice the likelihood of a
history of attempted suicide than PC patients (21% vs. 12%, x2=21.05, p<0.0001).
Other measures showed less substantial differences – Slightly more SC patients endorsed suicidal ideation in the last
week (i.e., had thoughts within the week that life was not worth living: 50.8% vs. 45.3%, p=0.0456 by IDS- C30, Table 4; 45.4% in PC, 50.8% in SC, p=0.0471 by HAM-D17,).
– Slightly more SC patients endorsed suicidal ideation in the last week (i.e., had thoughts within the week that life was not worth living: 50.8% vs. 45.3%, p=0.0456 by IDS- C30, Table 4; 45.4% in PC, 50.8% in SC, p=0.0471 by HAM-D17, Table 5).
Overall, 2.3% of PC patients and 3.4% of SC patients were clinically determined to be a current suicide risk at study entry (p=ns).
There was no difference between the proportion reporting a family history of suicide (approximately 5% of patients in each setting provided such a history).
How Effective is an SSRI in Real World Practice?
~ 30% met criteria for remission (HAM-D ≤ 7) ~ 50% met criteria for response (≥ 50%
decrease in depressive severity) 40% of those who remitted, and 56% of
those who responded, did so only at or after 8 weeks of treatment
Trivedi et al, Amer J Psychiatry, 2006)
Treatment Outcomes (% Remission)(L-2 Switch)
21.3
17.6
24.825.5 26.625.0
0
10
20
30
BUP-SR(n=239)
SERT (n=238)
VEN-XR(n=250)
Perc
ent
HRSD-17 QIDS-SR-16
Rush et al., N Engl J Med 2006;354(12):1231-42
Treatment Outcomes (% Remission)(L-2 Augmentation)
29.7 30.1
39.032.9
0
10
20
30
40
50
BUP-SR BUS
Perc
ent
HRSD-17 QIDS-SR-16
(n=279) (n=286)Trivedi et al., N Engl J Med 2006;354(12):1243-52
QIDS-SR16 Remission RatesThrough Levels 1 and 2
53.0%
30.6%32.9%
0
20
40
60
80
L-1 L-2* Overall
Perc
ent
* Theoretical
References Fava M, “Augmentation and Combination Strategies in Treatment Resistant
Depression”. J Clin Psychiatry, 2001; 62 (suppl 18): 4-11. Judd LL, Akiskal HS, Maser JD, et al. “Major Depressive Disorder: A Prospective
Study of Residual Subthreshold Depressive Symptoms as Predictor of Rapid Relapse”. J Affect Disord, 1998; 50: 97-108.
Gaynes, B.N., Rush, A.J., Trivedi, M., et al., A direct comparison of presenting characteristics of depressed outpatients from primary vs. specialty care settings: preliminary findings from the STAR*D clinical trial. General Hospital Psychiatry, 2005. 27(2): 87-96.
Rush AJ, Trivedi MH, Wisniewski SR, et al. Bupropion-SR, sertraline, or venlafaxine-XR after failure of SSRIs for depression. N Engl J Med. Mar 23 2006;354(12):1231-1242.
Trivedi MH, Fava M, Wisniewski SR, et al. Medication augmentation after the failure of SSRIs for depression. N Engl J Med. Mar 23 2006;354(12):1243-1252.
Trivedi M.H., Rush A.J, Wisniewski S.R. et al, “Evaluation of Outcomes with Citalopram for Depression Using Measurement-Based Care in STAR*D: Implications for Clinical Practice, Amer J Psychiatry, 2006. 163:1-13.