01Purpose and principlesWhat the treatment does and how it fits into care.
Psychiatric prescribing treats a defined syndrome and supports recovery in the person’s life. The same medicine may have several indications, with different starting doses, target doses and durations. Sedation alone does not establish successful treatment of depression or psychosis. Before selection, clarify diagnosis, severity, immediate risk, prior response and the patient’s priorities. Psychological treatment, social support and physical-health care remain part of the plan. Decisions about medicines should be revisited as circumstances and preferences change, especially when the burden of adverse effects becomes more apparent after acute symptoms settle.
A useful comparison considers both what the person hopes to gain and what they most want to avoid. Sexual adverse effects, weight change, sleepiness, gastrointestinal symptoms and monitoring visits can determine whether a medicine is acceptable. Explain likely onset and the review plan before prescribing so that early adverse effects or an initially limited benefit do not lead to an unplanned stop. Do not treat classes as interchangeable: antidepressants differ in interactions and withdrawal, antipsychotics differ in metabolic and neurological effects, and lithium requires a tightly coordinated monitoring system. Shared care must include explicit responsibility for prescribing, tests, results and escalation.
Key points
- Establish the indication and screen for bipolar symptoms, suicide risk, substance use and relevant physical illness before antidepressant prescribing.
- Select treatment with the person using expected benefit, previous response, adverse effects, interactions and overdose risk.
- For adult depression, the cited sertraline SmPC starts treatment at 50 mg orally once daily; increase only when indicated, by 50 mg at intervals of at least one week, maximum 200 mg daily.
- Review an antidepressant usually within two weeks, or within one week for people aged 18–25 or when suicide risk is a particular concern.
- Lithium requires timed levels and renal, thyroid and calcium surveillance; toxicity is a clinical assessment as well as a concentration.
- After more than 48 hours without clozapine, do not restart the previous maintenance dose; obtain specialist re-titration advice.
02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.
Ask about previous periods of unusually elevated or irritable mood, reduced need for sleep, increased activity and consequences suggestive of hypomania or mania. A depressive presentation may require a bipolar assessment rather than routine antidepressant monotherapy. Substance use, physical illness and current medicines may also contribute to symptoms and change the safest plan.
Nausea, restlessness or sleep disturbance may appear early with an antidepressant before sustained benefit is evident. Review worsening mood, activation and emerging suicidal thoughts promptly. Distinguish an expected tolerability issue from dangerous deterioration; an instruction to wait several weeks for benefit must not discourage seeking help for new risk.
Akathisia can look like worsening anxiety or agitation, while rigidity, fever and autonomic disturbance suggest a more serious syndrome. Serotonergic combinations may produce clonus and hyperreflexia. Examine the person and reconstruct recent changes rather than assuming all new behavioural symptoms reflect the underlying psychiatric diagnosis.
Weight gain, metabolic abnormalities, postural hypotension, sexual dysfunction and movement disorders can substantially affect functioning. Ask specifically because patients may not volunteer embarrassing or gradually developing symptoms. Physical changes deserve clinical assessment even when mental-state symptoms have improved and the medicine seems successful in that respect.
03Assessment before treatmentTests and checks that guide safe selection.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Mental-state and risk assessmentFirst step - Why
- Establish treatment need and the safety of the proposed setting.
- Interpretation and limitations
- Assess symptoms, function, suicidal thoughts, self-harm risk, mania, psychosis, substance use and support. A symptom scale can structure follow-up but cannot replace a conversation about intent, access to means or rapidly changing risk. Determine whether urgent specialist assessment is needed before routine prescribing.
- 02
Baseline physical assessment - Why
- Identify factors that affect selection and establish monitoring comparators.
- Interpretation and limitations
- Review weight, blood pressure, medical history, pregnancy possibility and interacting medicines. Before antipsychotic treatment, NICE includes metabolic and physical baseline assessment such as glucose or HbA1c, lipids, prolactin and movement-disorder evaluation; consider ECG according to the product and clinical risk. Record findings so later change is interpretable.
- 03
Lithium-specific assessment - Why
- Ensure the patient can begin or continue treatment within a safe monitoring system.
- Interpretation and limitations
- Check kidney function, electrolytes, thyroid function, calcium, weight and pregnancy status where relevant, with ECG when cardiovascular risk warrants it. Confirm the brand and formulation. A lithium concentration must be interpreted with the interval since the last dose; routine samples are taken 12 hours after dosing.
- 04
Adherence and exposure reconstruction - Why
- Explain poor response, withdrawal or altered psychotropic concentrations.
- Interpretation and limitations
- Ask non-judgmentally about missed doses, recent re-starts, changes in smoking, acute illness and newly purchased medicines. Verify specialist supplies separately from the GP repeat list. For clozapine, establish the exact last dose and contact the treating service before deciding how to resume after interruption.
04Treatment approachPreparation, options, escalation and aftercare.
01Worked caseStart an antidepressant with early reviewFirst stepA 24-year-old has a depressive episode with substantial functional impairment and chooses medication after discussing treatment options. There is no history suggesting mania, no current suicidal intent, no interacting medicine and no relevant hepatic disease; reliable follow-up is available.+
- 1Confirm the diagnosis and risk assessment, discuss previous treatment and agree a functional goal such as returning to regular work attendance. Explain that psychological support remains available and that medication selection can be revisited if the adverse-effect profile is unacceptable.
- 2EscalationIf sertraline is selected, prescribe 50 mg orally once daily for depression, using the product-specific regimen in the prescribing section. Discuss common adverse effects and what to do if symptoms worsen; avoid promising immediate relief or automatic dose escalation.
- 3Arrange review within one week because the person is aged 18–25. Give a contact route for worsening agitation, suicidal thinking or other concerning symptoms before that appointment, and agree what support is available outside routine hours.
- 4At review, assess adherence, tolerability, mental state and risk. Determine whether to continue, adjust or obtain specialist input. A short period without full improvement is expected to be interpreted in context, while emergent dangerous symptoms require immediate action.
- 5Verify later improvement against the agreed functional goal. Explain that successful treatment commonly continues for at least six months after remission with review, and that stopping should use an individual reduction plan rather than abruptly ending tablets when mood improves.
02Antipsychotic treatmentUse a documented therapeutic trialA person with psychosis is being assessed for antipsychotic treatment under an appropriate specialist plan.+
- 1Discuss candidate medicines with the person, including likely metabolic, neurological, hormonal and cardiovascular effects. Record which risks matter most to them and how previous experiences influence the choice.
- 2Complete relevant baseline assessment and start within the lower end of the licensed range, titrating according to the selected product and specialist plan. Specify the target symptoms and expected trial period; do not use several regular antipsychotics as an unexamined default.
- 3Monitor both mental-state response and physical effects during titration. Check for akathisia or other movement symptoms before interpreting restlessness as treatment-resistant illness. Address smoking changes and interactions where relevant to the chosen medicine.
- 4At review, decide whether there has been an adequate tolerated trial with meaningful benefit. Document reasons for continuation or switching and communicate monitoring ownership between specialist and primary-care teams.
03High-risk continuityManage lithium and clozapine safely during changeA patient on an established specialist psychotropic regimen presents during acute illness, admission or a treatment interruption.+
- 1For lithium, review hydration, kidney function and interacting medicines, especially purchased NSAIDs. If toxicity is suspected, withhold lithium, obtain urgent levels and electrolytes and seek specialist advice; do not wait for a routine monitoring appointment or rely on a previously therapeutic result.
- 2Check lithium levels one week after initiation or a dose change and weekly until stable. NICE’s usual initial target in bipolar treatment is 0.6–0.8 mmol/L; the prescribed milligram dose and any different target require an individual specialist plan.
- 3For clozapine, verify the last dose, blood-monitoring arrangements and current physical state. An interruption longer than 48 hours requires specialist re-titration; restarting a previously tolerated full dose risks serious hypotension and other toxicity.
- 4Investigate fever, chest pain, severe constipation or abdominal symptoms promptly in a clozapine-treated person. Infection and smoking cessation may increase exposure, so obtain specialist advice on levels and dosing and ensure the acute team communicates with the monitoring service.
05Regimens, contraindications and interactionsTreatment details and the circumstances that modify them.
Sertraline for an adult depressive episode
Start 50 mg orally once daily; if needed and tolerated, increase by 50 mg at intervals of at least 1 week, maximum 200 mg daily. Review early and continue an effective regimen for at least 6 months after remission before reassessing longer-term need.Check bipolar features, suicide risk, serotonergic interactions and MAOI contraindications. Use a lower or less frequent dose in hepatic impairment and avoid severe hepatic impairment; consider bleeding, hyponatraemia and sexual adverse effects. Reduce gradually when stopping.
Mirtazapine for an adult major depressive episode
The cited UK SmPC allows 15 or 30 mg orally daily initially; a selected cautious start is 15 mg at night. Effective doses are usually 15–45 mg daily; assess response over 2–4 weeks. NICE supports continuing effective depression treatment for at least 6 months after remission, with review.Sedation and weight gain may limit acceptability. Review renal or hepatic impairment, other sedatives, bipolar features and suicide risk. Avoid relevant MAOI combinations; fever or sore throat warrants prompt assessment for possible blood dyscrasia. Plan gradual withdrawal and continuation review after recovery.
06Complications, monitoring and follow-upAdverse effects, response and longer-term review.
- Review antidepressant treatment usually within two weeks, and earlier when age or suicide risk indicates. Assess symptoms, functioning, adherence and adverse effects together; check risk again after dose changes or deterioration.
- Check lithium levels every three months during the first year, then every three to six months once stable. Renal function, electrolytes, thyroid function and calcium are generally checked every six months. Increase frequency for risk factors, interactions or clinical change; confirm that samples were correctly timed.
- During antipsychotic treatment, follow weight and metabolic measures, blood pressure, movement symptoms, prolactin-related problems and relevant cardiac risk. Agree who owns each check and act on deteriorating physical health rather than recording results without a plan.
- Before discontinuing a long-term psychotropic, distinguish relapse prevention from current symptom suppression and discuss previous withdrawal experience. Coordinate gradual change with the person and relevant specialist, including what to do if mood, sleep or behaviour destabilises.
07Special situationsVariants, exceptions and circumstances that change the usual approach.
Valproate reproductive safeguards
For new valproate treatment in anyone under 55, two specialists must independently document that no other effective or tolerated treatment exists, or compelling reasons make reproductive risks inapplicable. People who can become pregnant must meet Pregnancy Prevention Programme conditions. Men should use condoms plus contraception used by their female partner during treatment and for three months afterwards. Existing male treatment does not require the same second-specialist review. Obtain specialist advice rather than abruptly stopping.
Stopping smoking changes exposure
For medicines affected by smoke-related enzyme induction, stopping cigarettes can alter concentrations even if nicotine replacement continues. Record changes in smoking during admission and discharge. The effect depends on the medicine; seek specific advice rather than applying the same dose adjustment to every psychotropic.
Withdrawal is not identical to relapse
Rapid onset of unfamiliar symptoms after dose reduction may suggest withdrawal, while recurrence of the original disorder has its own pattern. Both can coexist. Review timing and severity and adjust the plan instead of interpreting every symptom as proof of treatment failure.
Shared care needs acceptance
A monitoring request sent to another team does not establish that the team has accepted responsibility. Confirm the arrangement, ensure access to results and give the person a clear contact route. High-risk treatment is vulnerable when prescribing and surveillance become disconnected.
08Common pitfallsFrequent interpretation and management errors.
- 01
Treating new agitation as worsening psychiatric illness without checking akathisia, serotonin toxicity or withdrawal can lead to harmful additional medication.
- 02
Restarting clozapine at its previous full dose after a substantial interruption ignores loss of tolerance and can cause serious cardiovascular collapse.
- 03
Increasing lithium after one low result without checking timing, missed doses and the clinical state may convert a sampling problem into toxicity.
- 04
Using an antidepressant dose from one indication for another can produce unnecessary early adverse effects; check the indication-specific starting regimen.