3.3 Psychopharmacology and Substance Effects

Medication knowledge without exceeding scope

EPPP psychopharmacology items usually ask what a psychologist should recognize, assess, document, communicate, or refer — not how to prescribe. Prescriptive authority (RxP) exists for specially trained psychologists in only a small number of jurisdictions (for example New Mexico, Louisiana, Illinois, Iowa, Idaho, and a few others); most psychologists do not prescribe. The exam still expects you to know that medications and substances affect mood, cognition, sleep, movement, motivation, risk, and treatment engagement.

Study classes by clinical purpose and common concern rather than memorizing every brand name.

Key watch-outs the EPPP favors: lithium requires serum monitoring because therapeutic and toxic levels are close; monoamine oxidase inhibitors (MAOIs) require a tyramine-restricted diet to avoid hypertensive crisis; serotonin syndrome (agitation, hyperthermia, clonus) can follow serotonergic combinations; and abrupt benzodiazepine or alcohol withdrawal can cause seizures and is medically dangerous.

Substance effects in the differential

Intoxication can produce mood, anxiety, psychotic, cognitive, and behavioral symptoms. Withdrawal can create insomnia, irritability, dysphoria, tremor, agitation, confusion, or medical danger. Tolerance means the same dose produces a smaller effect; dependence involves physiological adaptation; and substance-induced symptoms must be ruled out before settling on a primary psychiatric diagnosis (for example, a stimulant or cannabis-driven anxiety presentation, or alcohol-related depression).

Adherence is psychological

Clients stop medication because of side effects, cost, stigma, cultural beliefs, pregnancy concerns, mistrust, low insight, cognitive impairment, or poor prescriber communication. A strong answer explores barriers and supports informed decision-making rather than scolding.

Scenario pattern. A client on an antipsychotic reports new restlessness and inability to sit still. The strong response considers akathisia, assesses distress and safety, and coordinates with the prescriber rather than labeling the client noncompliant. Scenario pattern. A client with panic uses heavy caffeine and intermittent cannabis; assess substance timing because both can trigger anxiety, while still considering panic disorder, trauma, and medical causes.

Scope reminders:

• Do not start, stop, or change medication unless legally authorized and competent.
• Do ask about drug name, reported dose, timing, adherence, perceived benefits, side effects, and prescriber contact.
• Do push for urgent care when symptoms suggest overdose, severe reaction, withdrawal risk, or imminent danger.
• Do obtain releases for coordination while respecting confidentiality and jurisdictional law.

Pharmacokinetics and special populations

The EPPP expects broad awareness of how the body handles drugs. Pharmacokinetics (absorption, distribution, metabolism, excretion) explains why dosing varies; hepatic metabolism via cytochrome P450 enzymes is the basis of many interactions. Pharmacodynamics concerns the drug's effect at receptors (agonist, antagonist, partial agonist). Older adults often need lower doses because of slowed metabolism and heightened sensitivity (especially to anticholinergic and sedative effects, which raise fall and delirium risk).

Children and adolescents carry specific warnings — for example, the boxed warning about increased suicidal thinking with antidepressants in youth, which makes monitoring essential. Pregnancy and lactation add risk-benefit complexity that belongs with the prescriber, though the psychologist should know to raise the question.

Recognizing dangerous syndromes

A handful of medication emergencies recur on the exam. Neuroleptic malignant syndrome (high fever, rigidity, altered mental status, autonomic instability) is a rare but life-threatening antipsychotic reaction requiring emergency care. Serotonin syndrome (agitation, hyperthermia, tremor, clonus) follows excess serotonergic activity. Lithium toxicity (coarse tremor, confusion, ataxia, vomiting) can be fatal. The correct psychologist response to any of these is urgent medical referral, not watchful waiting. Recognizing the pattern and acting on it — rather than knowing the precise pharmacology — is what items reward.

Even though this chapter teaches Part 1 knowledge, Part 2-Skills items reuse the same reasoning: how to communicate a medication concern, consult, document risk, secure informed consent, or adapt treatment when biological variables affect functioning. The throughline is that recognition plus appropriate coordination, inside scope, is almost always the keyed answer.

A final exam tip: when a stem offers an option to act unilaterally on medication (telling a client to stop, increase, or skip a dose) and another to consult the prescriber, the consult option is nearly always correct for a non-prescribing psychologist. When a stem describes a possible overdose, severe reaction, or withdrawal seizure risk, the emergency-referral option outranks any therapeutic interpretation. Reading carefully for these safety and scope cues lets candidates eliminate two or three distractors quickly, even on items where the underlying pharmacology is unfamiliar.