NR 606 Week 2 Partial Response Analysis Example

Partial Response Analysis: Whether D.L.'s Ten Weeks on Sertraline Qualify as an Adequate Trial, What Is Still in the Room and Five Explanations in Rank Order

Student Name

College of Nursing, Chamberlain University

NR 606: Diagnosis & Management in Psychiatric-Mental Health II Practicum

Instructor Name

Month Day, Year

Partial Response Analysis: Whether D.L.'s Ten Weeks on Sertraline Qualify as an Adequate Trial, What Is Still in the Room and Five Explanations in Rank Order

Two Claims That Sound Alike

Claim one: sertraline has done some work for D.L. That is clearly true; PHQ-9 fell from 22 to 12, mood lifted and suicidal thinking resolved.

Claim two: sertraline has done everything it is going to do. That is a different claim, and it cannot be made until the trial is shown to have been adequate.

Did the Trial Qualify

Dose: sertraline 50 mg for two weeks, 100 mg for two weeks, then 150 mg for six weeks. 150 mg is within the usual effective range; the maximum is 200 mg.

Duration: six weeks at 150 mg. Most guidance treats four to eight weeks at an adequate dose as a reasonable trial before judging response.

Adherence: pharmacy records show fills every 30 days without gaps. But when asked "In the last two weeks, how many days did you not take it?" D.L. said "probably weekends, most of them," because the tablet sits beside the coffee maker at work and D.L. does not go to the office on weekends. That is about four missed days in fourteen, roughly 70% of doses taken.

So the trial has not yet qualified. A dose of 150 mg taken five days a week is not a dose of 150 mg.

Tolerability as an Explanation

Asked directly about side effects: mild nausea in the first two weeks, now gone; delayed orgasm since the dose reached 150 mg, which D.L. described as "annoying but not a deal breaker"; no agitation, no headache. D.L. denied skipping doses because of the sexual side effect; the weekend gaps are about routine. Tolerability does not explain the shortfall, but the sexual side effect needs watching, since it often becomes a reason to stop later.

The Residual, Named

Reading the PHQ-9 item by item, as the scale allows (Kroenke et al., 2001), the total of 12 is made up mostly of four items: sleep (3), tiredness (3), concentration (2) and interest (2). Mood is now 1, and suicidal thinking 0.

D.L. drops off without trouble yet surfaces repeatedly through the night, feels unrefreshed in the morning and is exhausted by mid-afternoon. According to the partner, D.L. snores heavily and sometimes stops breathing for a few seconds. Body mass index is 33. Blood pressure is 142/90.

Explanations in Rank Order

1. Inconsistent dosing. About 30% of doses missed on weekends. This could account for some of the shortfall and is the cheapest to fix.

2. Obstructive sleep apnea. Unrefreshing sleep, daytime fatigue, poor concentration, snoring, witnessed pauses, obesity and raised blood pressure. A STOP-Bang score of 6 places D.L. at high risk (Chung et al., 2016). Sleep apnea would explain exactly the symptoms that did not move, and no antidepressant would treat it.

3. Depression not yet fully treated. Possible, and the dose could rise to 200 mg. But this explanation predicts that all symptoms would lag together, not that mood would improve while sleep, energy and concentration stayed put.

4. Incomplete diagnosis. A bipolar spectrum disorder can present as partial response to an antidepressant. Mood Disorder Questionnaire negative; no history of elevated mood. Unlikely.

5. Alcohol or other substances. Two glasses of wine on Friday and Saturday; AUDIT-C 3. Unlikely to explain the residual.

What It Implies

Before any change to sertraline: fix the weekend dosing by moving the tablet home and taking it at breakfast every day, with a phone reminder; and refer for a sleep study. Once both are addressed, the trial can be judged fairly.

In the STAR*D program, many patients who did not remit on the first step did so later, but each step assumed the previous one had been an adequate trial (Rush et al., 2006). Getting the first step right matters for every step after it.

What a Fair Trial Would Look Like

For the next four weeks, a fair trial of sertraline 150 mg means a dose every day, including weekends, confirmed by D.L.'s own count and by a pill box checked at the next visit. If D.L. is still at a PHQ-9 above 10 after four weeks of daily dosing and with the sleep study result in hand, the trial will have qualified, and claim two can be tested properly.

Why Not Increase the Dose Now

Raising sertraline to 200 mg now would be reasonable if the trial had qualified. It has not, and increasing the dose while doses are being missed would mean the patient takes more on weekdays and none on weekends. It would also raise the sexual side effect before the more likely explanations have been tested. The cheapest, safest step comes first.

What Was Ruled Out Quickly

Hypothyroidism: thyroid-stimulating hormone normal at intake. Anemia: complete blood count normal. Medicines that cause fatigue: none other than sertraline.

What the Partner Added

Collateral from someone who sees D.L. at night was the only way to learn about the breathing pauses, since D.L. was unaware of them and had never been asked.

With D.L.'s permission, the partner joined the visit by phone for five minutes. The partner confirmed the snoring and the pauses, added that D.L. often falls asleep in front of the television by 20:00 and said that weekends are when D.L. "seems most down." That last point fits both explanations at once: weekends are when doses are missed, and when there is no work structure to push through fatigue.

What D.L. Was Told

That the medicine has helped the mood but not the sleep and energy, that missing weekend doses may be part of the reason and that the snoring and tiredness may point to sleep apnea, which is treatable and can make depression harder to shift. D.L. was surprised by the weekend count and agreed to the reminder. D.L. was reluctant about a sleep study, worried about wearing equipment at night, and agreed after hearing that it can be done at home.

Next Review

Four weeks: PHQ-9 item by item, adherence count and the sleep study result. If the sleep study is positive, the next note will be a comorbidity plan rather than a medication change. If it is negative and dosing has been daily, the dose question becomes the main one.

References

Chung, F., Abdullah, H. R., & Liao, P. (2016). STOP-Bang Questionnaire: A practical approach to screen for obstructive sleep apnea. Chest, 149(3), 631-638. https://doi.org/10.1378/chest.15-0903

Kroenke, K., Spitzer, R. L., & Williams, J. B. W. (2001). The PHQ-9: Validity of a brief depression severity measure. Journal of General Internal Medicine, 16(9), 606-613. https://doi.org/10.1046/j.1525-1497.2001.016009606.x

Rush, A. J., Trivedi, M. H., Wisniewski, S. R., Nierenberg, A. A., Stewart, J. W., Warden, D., Niederehe, G., Thase, M. E., Lavori, P. W., Lebowitz, B. D., McGrath, P. J., Rosenbaum, J. F., Sackeim, H. A., Kupfer, D. J., Luther, J., & Fava, M. (2006). Acute and longer-term outcomes in depressed outpatients requiring one or several treatment steps: A STAR*D report. American Journal of Psychiatry, 163(11), 1905-1917. https://doi.org/10.1176/ajp.2006.163.11.1905