| Course | NU671 PMHNP Psychopathological Disorders and Psychotherapy |
|---|---|
| Unit | Unit 4 |
| Paper type | Etiological model application |
| Length | About 1,100 words, 7 pages double-spaced |
| Format | APA 7 student paper |
| School | Purdue University Global |
| Program | MSN |
| Updated | September 2026 |
Free sample paper for NU671 Unit 4
Why Her and Why Now? A Diathesis-Stress Model Applied to Depression in a 47-Year-Old Branch Manager Caring for Her Father With Dementia
[Student Name]
Purdue University Global
NU671: PMHNP Psychopathological Disorders and Psychotherapy
Unit 4 Etiological Model Application
[Instructor Name]
[Date]
The patient is composite; details are bracketed.
The Patient and the Question
Ms. [R.] is a [47]-year-old branch manager at a regional bank. Her father, [79], has Alzheimer disease, and since his fall in [March] she has driven to his apartment every morning before work and every evening after. She manages his medications, bills and appointments, and on weekends she stays overnight. By June she met criteria for a major depressive episode: a sad mood on most days, no pleasure in her garden or her choir, sleeping [ten] hours but waking unrefreshed, poor concentration at work and thoughts that she is "failing everyone." Her brother, who lives [40] minutes away and visits on Sundays, is tired and frustrated but not depressed.
The diathesis-stress model proposes that disorder arises when a vulnerability, the diathesis, meets a stressor of sufficient size, and that the two interact: the greater the vulnerability, the smaller the stress needed to produce an episode (Monroe & Simons, 1991). Applied to Ms. [R.], the model asks two questions. What made her vulnerable? And why was this stress enough?
The Diathesis: What She Brought to March
Three features of her history form the diathesis.
1. Family history. Her mother had recurrent depression, with two hospitalizations. In a large study of female twins, genetic liability affected the risk of depression partly by altering sensitivity to stressful events. In women at the lowest genetic risk, the predicted monthly probability of onset rose from [0.5] percent without a severe event to [6.2] percent with one; in those at the highest risk, from [1.1] percent to [14.6] percent (Kendler et al., 1995). Her mother's illness does not make depression inevitable for her, but the twin data suggest it may more than double the effect of the same stressful year.
2. A prior episode. At [22], after a broken engagement, she had a depressive episode lasting about [five] months that resolved without treatment. Prior episodes matter to the model. In the same female twin population, the association between stressful life events and new depressive episodes weakened as the number of previous episodes increased, up to about nine, consistent with the kindling hypothesis that the brain becomes more prone to depression with each episode (Kendler et al., 2000). With one previous episode, she is early in that process: past episodes have probably lowered her threshold somewhat, but a large stressor is still likely to be needed.
3. A way of thinking. She describes herself as the one who holds everything together and says she has always felt responsible for her mother's moods. She holds high standards for herself and blames herself when things go wrong. This style is not a diagnosis, but it is the kind of cognitive vulnerability that cognitive theories place inside the diathesis.
The Stress: What March Brought
The stressor is caregiving for a parent with dementia, added to a demanding job. It is chronic rather than a single event, and it includes several specific stresses: loss of sleep on weekend nights, loss of time for her own activities, the grief of watching her father decline, and role conflict between work and care.
Caregiving has a measurable effect on mood. A meta-analysis of [84] studies found that caregivers of frail older adults had higher levels of depression than noncaregivers, with the largest difference for depression among all outcomes studied, and larger differences for those caring for someone with dementia (Pinquart & Sörensen, 2003). By that evidence, her stressor is one of the stronger ones a middle-aged adult commonly faces.
The Interaction: Why Her, and Why Her Brother Differs
Her brother shares half of her genes, grew up in the same household and faces the same father. The model explains the difference through both sides of the equation. On the diathesis side, he has never had a depressive episode, and he describes a less self-blaming style. On the stress side, his exposure is smaller: one visit a week, no overnight stays, and no responsibility for medications or bills. The same father produced very different stress loads, and those loads landed on different vulnerabilities.
This comparison also shows a limit of the model. It is hard to separate how much of the difference comes from the diathesis and how much from the dose of stress, since in real families the more vulnerable sibling may also take on more of the burden, sometimes because of the very traits that make her vulnerable, such as a strong sense of responsibility.
A Rival Reading: Stress She May Also Generate
A diathesis-stress account treats the stress as something that happened to her. Hammen offered a complementary view: women with unipolar depression in her study experienced more stressful events than comparison groups, especially interpersonal events and events that depended at least partly on their own behavior, which suggests that people prone to depression can also generate some of their stress (Hammen, 1991). Some of Ms. [R.]'s load fits this reading. She declined her brother's offer to take the weekend overnights in [April] because she did not trust him to manage the medications, and she has not asked her employer for flexible hours. Neither choice is a fault, but both increased the dose of stress she then had to carry. Seeing this is useful clinically, because it identifies stress she has some power to reduce.
What the Model Adds and What It Cannot Do
The model adds three things to her care. First, it gives a non-blaming explanation she can accept: she is not weak, but a person with a known vulnerability under a heavy and prolonged stress. Second, it points to targets on both sides. The stress can be reduced through respite care, adult day services for her father, a conversation with her brother about sharing tasks, and a review of her work hours. The vulnerability can be addressed through treatment of the current episode and through cognitive work on her sense of total responsibility. Third, her prior episode and family history argue for continuing treatment after she recovers, since her risk of future episodes is raised.
What the model cannot do is predict precisely. The twin findings describe probabilities in women as a group, and the kindling findings describe averages across many people. Neither tells us exactly how much her mother's illness or her own first episode contributed. The model organizes her history; it does not measure it.
References
Hammen, C. (1991). Generation of stress in the course of unipolar depression. Journal of Abnormal Psychology, 100(4), 555-561. https://doi.org/10.1037/0021-843X.100.4.555
Kendler, K. S., Kessler, R. C., Walters, E. E., MacLean, C., Neale, M. C., Heath, A. C., & Eaves, L. J. (1995). Stressful life events, genetic liability, and onset of an episode of major depression in women. American Journal of Psychiatry, 152(6), 833-842. https://doi.org/10.1176/ajp.152.6.833
Kendler, K. S., Thornton, L. M., & Gardner, C. O. (2000). Stressful life events and previous episodes in the etiology of major depression in women: An evaluation of the "kindling" hypothesis. American Journal of Psychiatry, 157(8), 1243-1251. https://doi.org/10.1176/appi.ajp.157.8.1243
Monroe, S. M., & Simons, A. D. (1991). Diathesis-stress theories in the context of life stress research: Implications for the depressive disorders. Psychological Bulletin, 110(3), 406-425. https://doi.org/10.1037/0033-2909.110.3.406
Pinquart, M., & Sörensen, S. (2003). Differences between caregivers and noncaregivers in psychological health and physical health: A meta-analysis. Psychology and Aging, 18(2), 250-267. https://doi.org/10.1037/0882-7974.18.2.250
What the NU671 Unit 4 assignment asks for
In Unit 4 you apply an etiological model to one person's history to explain why a disorder developed when and in whom it did. Prompts usually specify or allow a choice of model, and they expect the model's components identified in the case, research evidence for each component, and an honest statement of what the model can and cannot explain. Four to six pages is typical. Graders look for application rather than description: the model should answer a question about this person, not appear as a textbook summary. Including a comparison, such as a sibling facing similar stress, is an effective way to test the model against the case. Implications for treatment and relapse risk strengthen the conclusion.
How this NU671 Unit 4 example is built
The paper opens with her caregiving routine, her symptoms and the question of why she, and not her brother, became depressed. The model is defined in two sentences. The diathesis section has three numbered parts, family history with the twin probabilities, a prior episode with the kindling findings, and a cognitive style, and a highlighted sentence interprets the twin data for her. The stress section describes the caregiving load and its size from the meta-analysis. The interaction section compares her with her brother on both sides of the model. A rival reading from Hammen identifies stress she may have generated. The final section lists what the model adds to her care and what it cannot predict.
NU671 Unit 4 rubric: what earns full points
The rubric for an etiological application usually covers the choice and explanation of the model, identification of its components in the case, quality of the supporting evidence, critical evaluation and clinical relevance. The components row rewards specific examples from the patient's history for each element of the model. Evidence points go to studies that match the element they support, such as twin research for genetic liability. Critical evaluation earns credit for naming limits, including the difficulty of separating vulnerability from the dose of stress within a family. Clinical relevance is judged on whether the model leads to targets for treatment and to a view of her future risk.
Common NU671 Unit 4 mistakes, and how to avoid them
A common mistake is summarizing the diathesis-stress model without applying it to the patient's history. Another is treating family history as proof of genetic cause, when twin studies describe group probabilities. Students often cite research on women for a male patient, or the reverse, without noting it. Some papers describe the stress but never measure its size or compare it with other stressors. Others ignore the possibility that the patient contributes to her own stress load, which the stress generation research raises. And a conclusion that the model fully explains her depression overstates what any etiological model can show about one individual.
Get an NU671 Unit 4 example written to your instructions
Your NU671 Unit 4 prompt probably names a model and supplies a person; send both, with the rubric, and say so if the model is left open. A free first application is written within 24-48h, every vulnerability tied to its evidence, the stressor weighed against them, and any second model adding what the first one missed. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.
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NU671 Unit 4 questions, answered
Which model fits when none is assigned?
Diathesis-stress suits questions about why one person developed a disorder when others facing the same stress did not. The biopsychosocial model suits questions about the full range of contributing factors. Many strong papers use one as the frame and the other as a check. Choose by the question the case raises, and say briefly why that model fits.
Is it acceptable to cite genetic research?
Yes, with care about what it shows. Family and twin studies support heritability at the population level without identifying any individual's genes. Candidate gene findings from the early 2000s mostly failed replication, and genome-wide studies show many variants with tiny effects. Cite the level of evidence precisely and avoid implying that family history determines an outcome.
Should the paper predict what will happen next?
A cautious prediction strengthens it, if tied to the model. Diathesis-stress implies higher relapse risk under future stress, and a biopsychosocial view suggests which supports might buffer it. State the prediction as a probability, name what would change it, and stop short of a treatment plan unless one is specifically requested.
Where can I find a free NU671 Unit 4 sample paper?
The complete NU671 Unit 4 etiological model application is shown on this page, with the diathesis, the stress, the comparison with her brother, the rival reading and the model's limits, plus five references. A paper applying a model to your own case can be drafted.
How does family history change risk in NU671 Unit 4?
The paper uses the Kendler twin study: in women at lowest genetic risk the monthly chance of onset rose from 0.5 to 6.2 percent after a severe event, and in those at highest risk from 1.1 to 14.6 percent. Genetic liability seemed to raise sensitivity to stress.