CSB601 Chap.4 Depression, Bipolar Disorder, Anxiety and Sleep
Depression, Bipolar Disorder, Anxiety and Sleep
Four conditions, one prescribing logic
Week 3 of the unit covers major depressive disorder, bipolar disorder, anxiety disorders and insomnia. Each follows the same pattern: psychological and lifestyle care at the base, a first-line drug class added by severity or poor response, and a signature safety problem that exam questions return to.
SSRIs lead for depression and anxiety, mood stabilisers lead for bipolar disorder, and hypnotics are short-course medicines only.
What the exam rewards
Questions reward precise links between receptor and adverse effect, the delayed onset of antidepressants, serotonin toxicity from stacked serotonergic products, and lithium as a high-risk medicine whose level depends on the kidneys.
Older adults on sedatives are a recurring falls scenario.
What this chapter covers
- 01
Depression Severity and Stepped Care
- 02
Antidepressant Classes and Receptors
- 03
Onset, Continuation and Tapering
- 04
Serotonin Toxicity Recognition
- 05
Bipolar Treatment and Lithium Safety
- 06
Anxiety, Insomnia and Benzodiazepines
Worked example · free
Lithium and an over-the-counter painkiller
- 2Mechanism: NSAIDs reduce renal perfusion, lithium clearance falls and the serum level rises towards toxicity because lithium has a narrow therapeutic index.
- 2Monitoring: lithium concentration, kidney function and thyroid function are the routine checks, and any new interacting drug is a reason to recheck the level.
- 2Action: screen the combination in AMH, eMIMS and AusDI with the MESS approach, avoid the NSAID, involve the prescriber and counsel her on toxicity signs.
Key terms
- Serotonin Toxicity
- A potentially fatal reaction to excess serotonergic activity, marked by fever, agitation, tremor, sweating, palpitations and diarrhoea.
- Tyramine Reaction
- A hypertensive crisis triggered when someone taking a non-selective MAOI eats aged or fermented foods.
- Narrow Therapeutic Index
- A property of a medicine whose effective and toxic concentrations lie close together, so small level changes matter.
- Anhedonia
- Loss of interest or pleasure in activities, one of the two core symptoms of a major depressive episode.
- Z-Drug
- A non-benzodiazepine hypnotic such as zolpidem or zopiclone, recommended only for short-term insomnia treatment.
Depression, Bipolar Disorder, Anxiety and Sleep FAQ
How long should I tell a patient to wait before deciding an antidepressant has failed?
Lecture material gives early improvement at one to two weeks, a meaningful response at three to four and full effect by four to six, occasionally eight. Workshop answers suggest about four weeks on one agent, with a dose increase considered before switching when the response is partial. Warn the patient that agitation or poor sleep can appear first, and arrange follow-up rather than an early change of drug.
Why are tricyclics rarely first-line if they work as well as SSRIs?
Their efficacy is similar, but blockade of muscarinic, histamine and alpha-1 receptors adds anticholinergic effects, sedation and falls, and overdose can cause arrhythmias, seizures and coma. That toxicity makes them a poor choice when suicide risk exists. Where a tricyclic is used in an older adult, nortriptyline is preferred, a baseline ECG is advised, and lying and standing blood pressure should be checked.
Can an antidepressant be used in bipolar depression?
Only as an adjunct with close monitoring, never alone, because monotherapy can precipitate mania. First-line options for bipolar depression are quetiapine, lamotrigine and lithium, often combined, alongside psychological therapy. In acute mania any antidepressant is stopped.
Electroconvulsive therapy is reserved for selected severe cases, and mood stabilisers should never be stopped suddenly because relapse risk is high without maintenance.
Are Z-drugs a safer alternative to benzodiazepines for older people?
No convincing evidence shows they are safer. Both are short-term options at the lowest dose, both add sedation and falls risk, and non-drug treatment such as CBT for insomnia comes first because its gains last. Benzodiazepines carry dependence, tolerance and withdrawal risks, and sedating antihistamines or antipsychotics are on the avoid list for sleep because of falls and anticholinergic burden.
Exam move
Build one table with four rows, one per condition, and four columns: non-drug anchor, first-line drug class, the class mechanism, and the single most examined risk. Then make a receptor sheet that links serotonin, noradrenaline, histamine, muscarinic and alpha-1 actions to their adverse effects, and test yourself by covering the effects column.
Draw the antidepressant onset timeline from memory, marking the review window and the continuation period after remission. For lithium, practise explaining the renal clearance chain aloud in under thirty seconds, then list the drugs that raise levels and the monitoring targets.
Finish each session with one mixed case containing several serotonergic products, and practise writing medication-related problems as possibilities rather than diagnoses, followed by efficacy issues, non-drug strategies and the members of the care team.
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