16.2 Psychiatric Diagnosis and Substance Use

The current FNP-BC Test Content Outline scores Psychiatric as one of the 13 body systems and lists psychiatric agents among the official drug-agent classes. Domain II is the diagnosis. Domain IV is the prescription, the safety plan, and the referral. You will not be asked to recite every DSM clause. You will be asked whether the score, the bipolar screen, and the next drug match the person in the room.

PHQ-9, GAD-7, and the suicide item

PHQ-9 scores the nine DSM depression items over two weeks. Teach the usual adult bands: 0–4 none or minimal, 5–9 mild, 10–14 moderate, 15–19 moderately severe, 20–27 severe. A score of 10 or more often justifies treating or stepping up treatment, but the number is not the whole visit. Item 9 asks about thoughts of being better off dead or of self-harm. A positive item 9 is a same-visit suicide assessment: ideation, plan, intent, means, prior attempts, intoxication, and whether the person can be safe until follow-up. Do not file a PHQ-9 of 16 with a circled item 9 and send the patient to the parking lot with a sertraline script.

GAD-7 scores anxiety: 0–4 minimal, 5–9 mild, 10–14 moderate, 15–21 severe. It supports a GAD diagnosis; it does not replace asking about panic, trauma, and substance use. Repeat both tools to evaluate response (Domain V). A falling score with restored function is a treatment success even if a residual 6 remains.

Ask every depressed or anxious patient about access to firearms and lethal medicines. Safety planning is Implementation, not extra credit.

DSM-pattern diagnoses the FNP must not mix

Major depressive disorder (MDD) is at least two weeks of depressed mood or anhedonia plus enough other features (sleep, interest, guilt, energy, concentration, appetite, psychomotor change, suicide) to reach five total, with impaired function. Grief can look similar; persistent functional collapse and worthlessness lean toward MDD.

Generalized anxiety disorder is excessive, hard-to-control worry on most days for at least six months, with restlessness, fatigue, concentration trouble, irritability, muscle tension, or sleep disturbance. Six days of exam stress is not GAD.

Panic disorder is recurrent unexpected panic attacks — abrupt surges of fear with palpitations, dyspnea, chest tightness, dizziness, or fear of dying — plus worry about more attacks or maladaptive avoidance. Rule out ACS when the first attack looks cardiac; do not send every subsequent stereotyped 10-minute surge to the catheterization lab.

PTSD requires a qualifying trauma plus intrusion (flashbacks, nightmares), avoidance, negative cognitions or mood, and hyperarousal, lasting more than a month. Trauma-focused psychotherapy is first-line; an SSRI can help. Do not start a standing benzodiazepine as PTSD treatment.

Bipolar spectrum disease is the trap that harms people. A prior week of decreased need for sleep, grandiosity, racing thoughts, risky spending or sex, and increased goal-directed activity is mania or hypomania until a psychiatrist helps you say it is not. Do not start antidepressant monotherapy when bipolar is suspected. An SSRI alone can precipitate mania. Screen before the first antidepressant: “Have you ever gone several days with almost no sleep and still felt wired or unstoppable?”

SSRI and SNRI: start, wait, watch, taper

First-line pharmacotherapy for unipolar MDD, GAD, panic, and PTSD is an SSRI (sertraline and escitalopram are common primary-care starts) or an SNRI (venlafaxine, duloxetine — useful when pain travels with mood). Start low, especially in older adults and people with panic, because early activation feels like a worse illness. An adequate trial is 4–6 weeks at a therapeutic dose. Ten days of “I feel the same” is not failure. If there is no meaningful response after a fair trial, switch within class or to the other class; do not stack three antidepressants in one visit.

Teach the boxed warning: antidepressants increase suicidal thinking and behavior in people younger than 25. That is a monitoring mandate — close follow-up in the first weeks, warn the family — not a ban on treating adolescent depression. Untreated MDD also kills.

Hyponatremia from SIADH clusters in older adults, especially women on diuretics. New confusion or a fall after an SSRI start is a sodium, not a “failed adjustment.” Citalopram prolongs QT: FDA maximum is 40 mg daily, and 20 mg daily in adults older than 60, with hepatic impairment, or with interacting CYP2C19 drugs. Escitalopram is cleaner for many older adults. Paroxetine and venlafaxine have ugly discontinuation syndromes — taper. Fluoxetine’s long half-life is more forgiving and is often preferred when pregnancy is possible, but no antidepressant is a casual pregnancy decision; involve obstetric collaboration.

Sexual side effects, GI upset, and early insomnia are expected counseling, not surprises at week six. Do not add a benzodiazepine as a lifelong patch for SSRI jitter.

ADHD, stimulants, and diversion

School-age ADHD is a two-setting diagnosis. Use Vanderbilt (or an equivalent validated) parent and teacher scales. Symptoms must be developmentally excessive, present before age 12 in the DSM pattern, and impairing. Adult ADHD is real; it is not a request for a stimulant the week of board exams without a childhood history and a substance review.

Stimulants (methylphenidate or amphetamine salts) are first-line for most school-age children after the diagnosis is solid. Before you prescribe, take a cardiovascular history: patient chest pain, syncope, unexplained palpitations, and a family history of sudden death or structural heart disease. A routine ECG is not mandatory in every healthy child, but a positive cardiac story is a pediatric-cardiology pause, not a first-fill. Measure blood pressure and pulse. Counsel appetite, sleep, and tics.

Nonstimulants (atomoxetine, extended-release guanfacine or clonidine) are preferred when there is active substance use, diversion pressure in the household, or stimulant-intolerant anxiety. Diversion is an Implementation problem: lock the bottle, count pills, use the lowest effective dose, prefer long-acting formulations, and do not write huge early refills for a college student you have never examined.

Substance use, the retired X-waiver, and crisis referral

SBIRT is the primary-care frame: Screen (single-item, AUDIT-C, DAST, or a validated equivalent), Brief Intervention (motivational language, not a lecture), Referral to Treatment when dependence or harm is established. Tobacco, alcohol, cannabis, stimulants, and opioids all count.

For opioid use disorder, medications save lives. Buprenorphine is a partial opioid agonist that reduces craving and withdrawal. Naltrexone is an antagonist and can be started only when the person is already opioid-free — giving it during active use precipitates withdrawal. Methadone remains opioid-treatment-program territory.

Know the current federal rule, because older review books are wrong. The DATA-2000 X-waiver was eliminated by the Mainstreaming Addiction Treatment Act (Consolidated Appropriations Act, 2023). You do not invent or need an X-waiver number. A clinician with a DEA registration that includes Schedule III authority may prescribe buprenorphine for OUD. The separate MATE Act training requirement attaches to DEA registration (generally a one-time 8-hour substance-use course for new or renewing registrations, with limited exemptions). State law, Medicaid rules, and employer credentialing can still add training, counseling, or documentation requirements. Teach the federal elimination plus the state-and-training caveat. Do not write a fake waiver ID on an exam essay and do not tell a patient that only psychiatrists can prescribe buprenorphine in 2026.

Alcohol withdrawal can kill. Red flags: prior withdrawal seizures or delirium tremens, tachycardia, hypertension, tremor, diaphoresis, visual hallucinations, agitation, and fever. That patient belongs in the emergency department for monitored benzodiazepines, thiamine, and glucose — not a chlordiazepoxide starter pack from primary care. Outpatient withdrawal is only for carefully selected low-risk people with support; when the stem is shaky, febrile, or hallucinating, you are not selecting them.

Benzodiazepines are short-term (days to a few weeks) for severe acute anxiety, alcohol withdrawal in the right setting, or brief crisis bridging. They are not first-line chronic GAD therapy, not PTSD treatment, and not a sleep plan for frail older adults (Beers). If you start one, write a stop date.

Refer to psychiatry for mania, psychosis, treatment-resistant depression after fair trials, diagnostic uncertainty, complex trauma, eating disorders with medical instability, and children whose presentation is not straightforward ADHD. Crisis / EMS / ED is for active suicidal intent with a plan and means, homicidal intent, inability to care for self, or withdrawing alcohol or benzodiazepines with instability. A same-week therapy referral is not a safety plan for someone who intends to act tonight.

FNP traps: starting fluoxetine in unrecognized bipolar disorder; ignoring PHQ-9 item 9; declaring an SSRI a failure at day 10; using citalopram 40 mg in a 72-year-old; writing a stimulant without Vanderbilt data or a cardiac history; telling patients they still need an X-waiver number; treating DTs in the office; and refilling alprazolam for years as “anxiety maintenance.”