Diagnosis and Treatment

This chapter teaches diagnostic reasoning and evidence-based treatment across the disorders the PMHNP manages. A standing rule governs everything here: diagnostic criteria sets from the DSM are copyrighted and are not reproduced — instead you learn the clinical reasoning that leads to a diagnosis, supported by public sources. Drug doses and warnings are cited facts, never advice.

Assessment tools and diagnostic reasoning

Diagnosis begins with the structured interview and validated instruments, interpreted against medical and substance-induced mimics. The differential for any psychiatric presentation includes medical disorders, substance and medication effects, and primary mental disorders, worked through with the assessment tools of Chapter 2. Age shapes the whole process: children, adults, and older adults present differently and tolerate treatments differently.

Depressive disorders

Major depression is among the most common and most treatable psychiatric conditions, and the VA/DoD clinical practice guideline gives the PMHNP a decision sequence. For initial pharmacotherapy — or for patients who previously responded well to medication — the guideline suggests offering bupropion, mirtazapine, a serotonin-norepinephrine reuptake inhibitor, trazodone, vilazodone or vortioxetine, or a selective serotonin reuptake inhibitor, not rank ordered^[1]. It suggests against esketamine, ketamine, monoamine oxidase inhibitors, nefazodone, or tricyclic antidepressants as initial pharmacotherapy^[1].

For severe depression (for example PHQ-9 above 20), persistent depression lasting more than two years, or recurrent depression with two or more episodes, the guideline suggests offering combined pharmacotherapy and evidence-based psychotherapy^[1]. When a patient shows partial or no response to an adequate trial of initial medication, the options are switching to another antidepressant (including TCAs, MAOIs, or agents from the earlier list), switching to psychotherapy, augmenting with psychotherapy, or augmenting with a second-generation antipsychotic^[1]. After partial or no response to two or more adequate pharmacologic trials, repetitive transcranial magnetic stimulation is suggested^[1]. For patients who have not responded to several adequate pharmacologic trials, ketamine or esketamine is suggested as an augmentation option^[1]. Patients who achieve remission with antidepressant medication should continue the antidepressant at the therapeutic dose for at least six months to decrease relapse risk^[1].

Pharmacogenomics refines antidepressant choice: in CYP2D6 poor metabolizers vortioxetine reaches higher concentrations and the maximum is 10 mg^[2], and in CYP2C19 poor metabolizers citalopram's maximum recommended dose is 20 mg because of QT-prolongation risk^[2]. Among complementary approaches, St. John's wort is not consistently effective for depression^[3], and combining it with certain antidepressants can lead to a potentially life-threatening increase in the body's levels of serotonin^[3].

Bipolar and related disorders

Bipolar disorder involves episodes of mania or hypomania alternating with depression, and accurate diagnosis separates it from unipolar depression because the treatments differ. Lithium remains a cornerstone mood stabilizer, with its thyroid and calcium monitoring requirements described in Chapter 1^[4]. Valproate is effective but carries the pregnancy, pancreatitis, and pediatric hepatotoxicity warnings every prescriber must know^[5]. Carbamazepine's risks include aplastic anemia, agranulocytosis, SIADH-related hyponatremia, and HLA-B*1502-linked severe skin reactions^[6]. Lamotrigine requires slow titration, especially with valproate on board^[7].

Schizophrenia spectrum and other psychotic disorders

Schizophrenia is a chronic brain disorder whose symptoms include delusions, hallucinations, disorganized thinking, and negative symptoms; antipsychotic medications are the pharmacologic mainstay. Second-generation antipsychotics carry metabolic risks that may increase cardiovascular and cerebrovascular risk^[8]. Clozapine is reserved for treatment-resistant illness because of its boxed warnings — severe neutropenia requiring baseline and ongoing ANC monitoring, orthostatic hypotension with bradycardia and syncope, seizure, and myocarditis or cardiomyopathy that can be fatal^[9]. In CYP2D6 poor metabolizers, aripiprazole and iloperidone need dosage adjustment, and pimozide has strict maximums^[2].

Anxiety disorders

Generalized anxiety disorder is characterized by persistent excessive worry; first-line treatments include SSRIs and cognitive behavioral therapy. Panic disorder responds to SSRIs as first-line pharmacotherapy with CBT as the psychotherapeutic standard. Specific phobias are treated primarily with exposure-based CBT. Buspirone and hydroxyzine appear among anxiolytic options, while benzodiazepines — effective short-term — carry the dependence and opioid-interaction warnings of Chapter 1^[10].

Obsessive-compulsive and related disorders

Obsessive-compulsive disorder is marked by uncontrollable recurring thoughts (obsessions) and repetitive excessive behaviors (compulsions), or both^[11]. First-line treatments are SSRIs and exposure and response prevention (ERP), a CBT variant; augmentation strategies exist for partial responders. The related disorders — body dysmorphic disorder, hoarding disorder, trichotillomania, excoriation — share the compulsive behavioral pattern and respond to related behavioral and serotonergic approaches.

Trauma- and stressor-related disorders

PTSD follows exposure to traumatic events such as natural disasters, acts of violence, or serious accidents, producing a range of reactions^[12]. The VA/DoD guideline recommends individual trauma-focused psychotherapy — prolonged exposure, cognitive processing therapy, or EMDR — over pharmacotherapy for PTSD^[13]. When medication is used, paroxetine, sertraline, or venlafaxine are suggested^[13]. Prazosin is suggested for the treatment of nightmares^[13]. The PC-PTSD-5 provides brief primary-care screening^[14].

Sleep-wake disorders

Chronic insomnia is treated first with cognitive behavioral therapy for insomnia (CBT-I), not medication: NCCIH notes that CBT-I is the treatment most strongly recommended for insomnia^[15], comprising sleep hygiene education, stimulus control, sleep restriction, and cognitive restructuring. Melatonin supplements may be helpful for sleep problems caused by shift work or jet lag^[15], while clinical trials of valerian have had inconsistent results and its value for insomnia has not been demonstrated^[15].

Substance-related and addictive disorders

Tobacco, alcohol, and drug use are assessed at every encounter and treated with combined pharmacologic and behavioral approaches. For alcohol use disorder, naltrexone, acamprosate, and disulfiram are the established medications — disulfiram blocking alcohol oxidation at the acetaldehyde stage and requiring at least 12 hours of abstinence before the first dose^[16], naltrexone requiring 7 to 10 opioid-free days first^[17]. Opioid use disorder is treated with methadone (through opioid treatment programs with daily supervised dosing), buprenorphine, or extended-release naltrexone, always paired with counseling. Motivational interviewing — expressing empathy, developing discrepancy, rolling with resistance, supporting self-efficacy — is the core counseling style, and peer support groups aid sustained recovery.

Neurodevelopmental disorders

CNS stimulants raise blood pressure (about 2 to 4 mm Hg) and heart rate (about 3 to 6 bpm), and sudden death has been reported in patients with structural cardiac abnormalities or other serious cardiac disease treated at recommended ADHD dosages^[18]. Atomoxetine is a non-stimulant option — with CYP2D6 poor-metabolizer titration cautions^[2].

Eating disorders

Anorexia nervosa, bulimia nervosa, and binge-eating disorder are diagnosed by their characteristic behavioral and physiologic patterns. Medical stabilization comes first in anorexia — refeeding is managed carefully — while bulimia and binge-eating disorder respond to CBT and, for binge eating, specific pharmacotherapy. Fluoxetine's SSRI labeling reminds prescribers that serotonin syndrome can occur with SSRIs alone or combined with other serotonergic agents^{[19, 20]}.

Neurocognitive disorders: delirium and dementia

Delirium is an acute, transient, usually reversible, fluctuating disturbance in attention, cognition, and consciousness level^[21]. Treatment is correction of the cause and supportive measures^[21]: correcting the cause and removing exacerbating factors may result in resolution of delirium^[21]. In dementia-related psychosis, elderly patients treated with antipsychotic drugs are at an increased risk of death^[8]; when medications are used for behavioral symptoms, risks are weighed explicitly with families.

Personality disorders

Borderline personality disorder is treated with dialectical behavior therapy, whose modules — mindfulness, distress tolerance, emotion regulation, and interpersonal effectiveness — are intended to improve emotion regulation skills^[22].

Somatic symptom, dissociative, and adjustment disorders

Somatic symptom disorder's first-line treatment is psychotherapy, particularly cognitive-behavioral therapy^[23]. Patients also benefit from a supportive primary-care relationship with regular visits, coordinated care, and protection from unnecessary tests and procedures^[23]. Dissociative disorders (disruptions of memory, identity, or consciousness) and adjustment disorders (maladaptive responses to identifiable stressors) complete the differential in this section.

Integrative treatment

Integrative approaches are evaluated by evidence: for sleep, CBT-I is the most strongly recommended treatment^[15], melatonin may help sleep problems caused by shift work or jet lag^[15], and valerian's value for insomnia has not been demonstrated^[15] — while kava's use has been linked to liver injury that is sometimes serious or even fatal^[15]. Each approach is weighed against interactions such as St. John's wort with serotonergic antidepressants, which can dangerously raise serotonin levels^[3].

Psychopharmacologic interactions with other drugs and substances

Chapter 1's interaction table is clinical practice here: lithium with NSAIDs, diuretics, ACE inhibitors, and metronidazole^[4]; lamotrigine with valproate^[7]; fluoxetine with thioridazine^[20] and other serotonergic agents^[20]; MAOIs with tyramine-containing foods^[24], with immediate discontinuation and blood-pressure-lowering therapy if hypertensive crisis occurs^[24]; benzodiazepines with opioids^[10]; stimulants with cardiac risk factors^[18]; and disulfiram only after at least 12 hours of alcohol abstinence^[16].

Psychotherapy and related theories in treatment planning

Treatment plans draw on evidence-based modalities matched to diagnosis: DBT's skills modules — mindfulness, distress tolerance, emotion regulation, interpersonal effectiveness — for emotion dysregulation^[22], motivational interviewing for substance use, and attention to transference phenomena in the therapeutic relationship^[25]. The plan matches modality to diagnosis, severity, patient preference, and evidence — combined treatment for severe, persistent, or recurrent depression being the clearest example^[1].

Chapter 3 Quiz — Diagnosis and Treatment

1. A patient with severe major depression with psychotic features has not responded to multiple medication trials. The PMHNP discusses electroconvulsive therapy. Which guideline statement supports considering ECT here?

• A. Recommended for psychotic depression
• B. Recommended only for mild depression
• C. Contraindicated in psychotic depression
• D. No role in resistant depression

2. A patient with chronic insomnia asks for a sleep medication as the first treatment. The PMHNP explains the evidence-based first-line approach. Which is it?

• A. Cognitive behavioral therapy for insomnia
• B. Immediate nightly benzodiazepine therapy
• C. Over-the-counter antihistamines long term
• D. Antipsychotic medication for sedation

3. A CYP2D6 poor metabolizer is prescribed atomoxetine for ADHD. The PMHNP follows the pharmacogenomic table. Which action does it state?

• A. Slower titration; increase if tolerated
• B. Double the starting dose
• C. No adjustment is ever needed
• D. Discontinue it immediately

4. A patient with newly diagnosed major depressive disorder has no prior medication trials. Following the VA/DoD guideline, which agent may the PMHNP offer as initial pharmacotherapy?

• A. Esketamine as a first-line option
• B. Bupropion among the suggested options
• C. A monoamine oxidase inhibitor first
• D. Nefazodone as the preferred agent

5. A patient has failed two adequate antidepressant trials. The PMHNP discusses repetitive transcranial magnetic stimulation. Which guideline statement supports this option?

• A. After two failed adequate trials
• B. Suggested before any medication trial
• C. Contraindicated in resistant depression
• D. A replacement for diagnostic assessment

6. An older adult with dementia develops psychosis, and the family asks about antipsychotic treatment. Which class-wide warning must the PMHNP discuss?

• A. Increased mortality in dementia-related psychosis
• B. Guaranteed improvement of memory symptoms
• C. No risks exist in elderly patients
• D. Antipsychotics cure the underlying dementia

7. A patient with PTSD has prominent nightmares that persist after a course of trauma-focused psychotherapy. Which medication does the VA/DoD guideline suggest for this symptom?

• A. Prazosin for trauma-related nightmares
• B. A benzodiazepine for nightly sedation
• C. An antipsychotic as the first choice
• D. A stimulant to suppress dreaming

8. The same guideline suggests against several agents for initial pharmacotherapy of MDD. Which agent belongs on the "suggest against" list for initial treatment?

• A. Sertraline as initial therapy
• B. Mirtazapine as initial therapy
• C. A tricyclic antidepressant initially
• D. Vortioxetine as initial therapy

9. When medication is chosen for PTSD, which agents does the VA/DoD guideline suggest?

• A. Paroxetine, sertraline, or venlafaxine
• B. Haloperidol, chlorpromazine, or fluphenazine
• C. Lithium, valproate, or carbamazepine
• D. Disulfiram, acamprosate, or naltrexone

10. A patient on phenelzine develops a sudden severe headache with very high blood pressure after a meal. The PMHNP recognizes a hypertensive crisis. Which immediate action does the label direct?

• A. Stop it; treat the blood pressure
• B. Reassure the patient and continue
• C. Double the next dose
• D. Wait a week before acting

11. A patient with treatment-resistant schizophrenia is evaluated for clozapine. Which baseline test does the label require before starting?

• A. Baseline absolute neutrophil count
• B. Baseline serum amylase level
• C. Baseline visual acuity testing
• D. Baseline pulmonary function testing

12. A patient on clozapine develops fever, chest pain, and palpitations. The PMHNP suspects a cardiac complication. Which labeled risk does this presentation suggest?

• A. Myocarditis or cardiomyopathy
• B. Benign orthostatic hypotension
• C. Expected mild tachycardia
• D. Chest wall muscle strain

13. A newly diagnosed PTSD patient asks about treatment options. The PMHNP explains the guideline's preferred first approach. Which is recommended over pharmacotherapy?

• A. Trauma-focused individual psychotherapy
• B. Long-term benzodiazepines alone
• C. Watchful waiting without treatment
• D. Group psychoeducation as the only treatment

14. A patient with alcohol use disorder who also takes prescribed oxycodone for back pain asks about starting naltrexone. Which statement is accurate?

• A. Stop opioids 7–10 days first.
• B. It can start while he takes oxycodone.
• C. It requires no preparation at all.
• D. It is used only after disulfiram fails.

15. A child with ADHD is starting a stimulant. The parents ask about cardiac safety. Which labeled warning does the PMHNP discuss?

• A. Sudden death with heart defects
• B. Stimulants have no cardiac effects
• C. Cardiac assessment is unnecessary
• D. Stimulants protect the heart

16. A patient shows partial response to an adequate trial of sertraline. Which next step does the VA/DoD guideline suggest?

• A. Continue the same dose unchanged
• B. Switch, add psychotherapy, or augment
• C. Stop treatment for six months
• D. Add esketamine first

17. A patient taking St. John's wort for mood also starts sertraline. The PMHNP warns about the combination. Which risk does the evidence describe?

• A. A dangerous rise in serotonin
• B. Loss of antidepressant effect in days
• C. Severe hypoglycemia
• D. No significant interaction

18. A patient has severe major depression with a PHQ-9 of 24. The PMHNP recommends combined treatment. Which guideline statement supports this?

• A. Combined medication and psychotherapy
• B. Psychotherapy alone for all severe depression
• C. Medication alone for all severe depression
• D. No treatment until symptoms become persistent

19. A patient with MDD achieves full remission on venlafaxine. How long does the guideline recommend continuing the antidepressant at the therapeutic dose?

• A. Two weeks after remission begins
• B. At least six months
• C. One month after remission begins
• D. Until the first missed dose occurs

20. A patient with borderline personality disorder asks about the most evidence-based psychotherapy. The PMHNP recommends which modality?

• A. Dialectical behavior therapy
• B. Psychoanalysis five times weekly indefinitely
• C. No psychotherapy has any evidence base
• D. Hypnosis as the primary treatment

21. A patient describes uncontrollable recurring thoughts and repetitive excessive behaviors. The PMHNP recognizes the NIMH description of which disorder?

• A. Generalized anxiety disorder presentation
• B. Obsessive-compulsive disorder presentation
• C. Panic disorder presentation
• D. Specific phobia presentation

22. A patient with delirium becomes agitated on the medical unit. The PMHNP prioritizes which intervention?

• A. Treat the underlying cause
• B. Start long-term antipsychotics
• C. Apply physical restraints first
• D. Discharge without evaluation

Sources cited in this excerpt

1. VA/DoD Clinical Practice Guideline for the Management of Major Depressive Disorder: Provider Summary, Version 4.0 (2022). U.S. Department of Veterans Affairs and Department of Defense. https://www.healthquality.va.gov/
2. Table of Pharmacogenetic Associations. U.S. Food and Drug Administration. https://www.fda.gov/medical-devices/precision-medicine/table-pharmacogenetic-associations
3. St. John's Wort and Depression: In Depth. NCCIH. https://www.nccih.nih.gov/health/st-johns-wort-and-depression-in-depth
4. DailyMed - LITHIUM CARBONATE- lithium carbonate capsule. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=04518b80-7563-4544-bf05-04f286223faa
5. DailyMed - DIVALPROEX SODIUM tablet, delayed release. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=15f8a5be-e269-2e07-60d9-1dd7bf5f5281
6. DailyMed - CARBAMAZEPINE tablet, chewable CARBAMAZEPINE tablet CARBAMAZEPINE tablet, extended release CARBAMAZEPINE suspension. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0526a054-3eda-49b4-b390-7d5d16e30af8
7. DailyMed - LAMOTRIGINE tablet. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=44670496-41ea-36a1-c435-32e359766a74
8. DailyMed - RISPERIDONE tablet, film coated. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=07d43bf6-a695-453a-a5c7-9581effe585c
9. DailyMed - CLOZAPINE tablet, orally disintegrating. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=09231d80-6343-4a34-bd5b-100c547fd3c9
10. DailyMed - LORAZEPAM injection, solution. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=20140b19-846b-425f-b191-670e17809945
11. Obsessive-Compulsive Disorder (OCD). National Institute of Mental Health (NIMH). https://www.nimh.nih.gov/health/topics/obsessive-compulsive-disorder-ocd
12. Traumatic Events and Post-Traumatic Stress Disorder (PTSD). National Institute of Mental Health (NIMH). https://www.nimh.nih.gov/health/topics/post-traumatic-stress-disorder-ptsd
13. VA/DoD Clinical Practice Guideline for Management of Posttraumatic Stress Disorder and Acute Stress Disorder: Provider Summary, Version 4.0 (2023). U.S. Department of Veterans Affairs and Department of Defense. https://www.healthquality.va.gov/
14. Primary Care PTSD Screen for DSM-5 (PC-PTSD-5) - PTSD: National Center for PTSD. https://www.ptsd.va.gov/professional/assessment/screens/pc-ptsd.asp
15. Sleep Disorders and Complementary Health Approaches: Usefulness and Safety (NCCIH). https://www.nccih.nih.gov/health/sleep-disorders-and-complementary-health-approaches
16. DailyMed - DISULFIRAM tablet. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=07abe950-3565-418c-8086-b804406a8c87
17. DailyMed - NALTREXONE HYDROCHLORIDE tablet, film coated. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=00c04ff4-b6f2-466c-9ab9-813a60577db0
18. DailyMed - AMPHETAMINE SULFATE tablet. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=00242264-40d8-4267-a91a-727a1f088616
19. DailyMed - SERTRALINE HYDROCHLORIDE solution, concentrate. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=01800452-c353-4235-a66a-214048752e74
20. DailyMed - FLUOXETINE capsule. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=05b0781b-50e2-4311-bde0-430b96e2ef8e
21. Delirium - Neurology - MSD Manual Professional Edition. https://www.msdmanuals.com/professional/neurologic-disorders/delirium-and-dementia/delirium
22. Emotion Regulation in Schema Therapy and Dialectical Behavior Therapy - PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC5021701/
23. Somatic Symptom Disorder - Psychiatry - MSD Manual Professional Edition. https://www.msdmanuals.com/professional/psychiatric-disorders/somatic-symptom-and-related-disorders/somatic-symptom-disorder
24. DailyMed - PHENELZINE SULFATE tablet. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=40483372-448f-4284-976c-8462ef256661
25. 4.3 Assessment – Nursing Mental Health and Community Concepts 2e. https://wtcs.pressbooks.pub/nursingmhcc/chapter/4-3-assessment/