Lucan · Conditions

Generalised anxiety disorder

Australian guidance: eTG Psychotropic, Anxiety and associated disorders (captured 2026-06-17, added to this note 2026-09-22) + RANZCP

1. Definition and epidemiology

Generalised anxiety disorder (GAD) is a chronic psychiatric condition characterised by excessive, difficult-to-control worry about multiple domains of life, accompanied by physical and cognitive symptoms that cause significant functional impairment. The 12-month prevalence in Australia is approximately 2.7% and the lifetime prevalence around 5.9%, making it one of the most common anxiety disorders in primary care. It is roughly twice as common in women as in men, with peak onset in the third decade, though a bimodal distribution is observed with a second rise in later life.

2. Pathophysiology

The neurobiology of GAD involves dysregulation of the cortico-limbic circuits that modulate threat appraisal and the fear response. The amygdala, prefrontal cortex, anterior cingulate cortex, and hippocampus form a network that in GAD demonstrates heightened amygdala reactivity with reduced prefrontal inhibitory control, resulting in sustained threat vigilance even in the absence of objective danger. At the neurochemical level, reduced GABAergic tone (the principal inhibitory neurotransmitter system) and relative excess of noradrenergic and serotonergic signalling contribute to the hyperarousal state. The hypothalamic-pituitary-adrenal (HPA) axis shows blunted cortisol suppression in response to dexamethasone in some patients, reflecting chronic stress dysregulation. Genetic factors account for roughly 30% of variance in heritability, and early adverse life experiences interact with genetic vulnerability to sensitise threat-processing circuitry. Cognitive models emphasise intolerance of uncertainty as a central maintaining mechanism, driving repetitive worry as a maladaptive coping strategy.

3. Clinical presentation and diagnostic criteria

The core feature is excessive anxiety and worry about a number of events or activities, occurring more days than not for at least six months, that the patient finds difficult to control. DSM-5 requires three or more of the following six associated symptoms in adults: restlessness or feeling keyed up or on edge, easy fatigability, difficulty concentrating or mind going blank, irritability, muscle tension, and sleep disturbance (difficulty falling or staying asleep, or restless unsatisfying sleep). In the ICD-11 framework, the equivalent category is generalised anxiety disorder and maps closely to DSM-5 criteria. On examination, patients frequently display a tense posture, psychomotor agitation, and signs of autonomic arousal such as tachycardia and diaphoresis. The Generalised Anxiety Disorder 7-item scale (GAD-7) is the validated self-report screening tool used in Australian primary care practice; a score of 10 or above indicates moderate to severe anxiety warranting formal assessment. The condition must cause clinically significant distress or functional impairment, and must not be attributable to a substance, another medical condition, or better explained by another mental disorder.

4. Investigations and AU-specific cutoffs

GAD is a clinical diagnosis; investigations are directed at excluding organic causes of anxiety rather than confirming the diagnosis.

Baseline bloods indicated in all new presentations include thyroid stimulating hormone (TSH; hyperthyroidism and hypothyroidism both precipitate anxiety), fasting plasma glucose (hypoglycaemia), full blood count, electrolytes, renal and hepatic function, and serum calcium (hypercalcaemia). A 12-lead ECG is appropriate if cardiac symptoms such as palpitations are prominent. Urine drug screen should be considered where substance-induced anxiety is suspected.

Specific AU cutoffs to note: TSH reference range is 0.4 to 4.0 mIU/L (most AU laboratories); fasting glucose above 7.0 mmol/L on two occasions defines diabetes as a potential contributing comorbidity. If phaeochromocytoma is clinically suspected, 24-hour urine metanephrines or plasma-free metanephrines are warranted. No neuroimaging is routinely required unless focal neurological signs are present. None of these cutoffs is carried by the captured eTG chapter, which records only that anxiety symptoms can be secondary to medical conditions such as hyperthyroidism, without giving laboratory thresholds.

The GAD-7 score of 10 or above is the AU primary care threshold for initiating treatment discussions. Not carried by the captured eTG chapter, which does not name the GAD-7 or give a score threshold.

5. Management

Management follows a stepped-care model consistent with eTG Psychotropic and RANZCP clinical practice guideline principles.

Step 1 involves psychoeducation, lifestyle modification (regular aerobic exercise, sleep hygiene, caffeine and alcohol reduction), and active monitoring. Validated self-help resources and digital mental health programs endorsed by Beyond Blue are appropriate first steps.

Step 2 involves structured psychological therapy. Cognitive behavioural therapy (CBT) is the psychotherapy with the strongest evidence base for GAD and is the recommended first-line psychological treatment. Acceptance and commitment therapy (ACT) and applied relaxation are alternatives where CBT is unavailable or not acceptable. In Australia, patients may access up to 10 individual and 10 group Medicare-subsidised psychological therapy sessions per calendar year under a GP Mental Health Treatment Plan (item 2700 series).

Step 3 involves pharmacotherapy when psychological therapy alone is insufficient or when symptom severity warrants earlier pharmacological intervention. First-line agents are the selective serotonin reuptake inhibitors (SSRIs) or serotonin-noradrenaline reuptake inhibitors (SNRIs). An adequate trial is defined as at least four to six weeks at therapeutic dose.

Benzodiazepines may be considered for short-term adjunctive use in severe acute anxiety but should generally not be used as monotherapy for GAD. The RANZCP Professional Practice Guideline 5 (2019) states that benzodiazepine use should be restricted to short-term periods, and that longer-term use should only be considered in patients who do not respond to adequate trials of other evidence-based pharmacological and psychological treatments. A small subset of patients with severe GAD who are unresponsive to multiple trials may derive benefit from long-term low-dose benzodiazepine therapy; this requires documented informed consent, one prescriber policy, and regular clinical review.

Corroborated 2026-09-22 by the captured eTG chapter, which carries benzodiazepine principles in its own right. eTG states that benzodiazepines are rapid acting, well tolerated and effective anxiolytics for the most prominent symptoms of anxiety with a strong evidence base, but that they should not be used as first-line therapy because of potential harms including increased risk of falls, memory problems, accidents, daytime sedation and dependence. Their use is usually restricted to acute crises and the immediate short term, and maintenance therapy may be appropriate in patients who have not responded to other treatments and in those who are stable on a long-term regimen with good clinical response, which supports this note's "small subset" paragraph. Caution is needed in older patients and in patients with a history of problem substance use, particularly problem alcohol use. Benzodiazepines with short half-lives (less than 6 hours) are not recommended for anxiety disorders because they are the most addictive. Historically it was thought that combining benzodiazepines with psychosocial treatment led to poorer outcomes; eTG records that this association has now been challenged and that there may be circumstances where patients use both modalities simultaneously. Not carried by the captured eTG chapter: the RANZCP Professional Practice Guideline 5 numbering and the one prescriber policy.

Added 2026-09-22 from the captured eTG chapter, prescribing safeguards and the general management frame. Assess the risk of misuse, including checking a prescribing register or prescription monitoring service and being wary of prescribing to unfamiliar patients who ask for a specific drug; discuss the potential for addiction with the patient; consider body size, age, comorbidities, drug history and previous response when selecting a dose, noting that older and frail patients may need doses lower than the recommended range; prescribe small quantities at a time; advise about the effects on driving, operating heavy machinery and other tasks requiring coordination and concentration; and specify the expected duration of therapy with regular review of response. More broadly, eTG directs a shared decision-making approach, with psychosocial interventions or pharmacotherapy both being appropriate initial options depending on the patient and the specific anxiety disorder; notes that anxiety disorders are often relapsing or chronic and require an adequate duration of therapy, and that symptoms may not completely resolve whatever therapy is used; and records that in young people there are few data on psychotropic use, that young people are more susceptible to activation and suicidal thoughts when starting an antidepressant (most often seen with SSRIs), and that pharmacotherapy should ideally be started by a clinician with expertise in psychotropics in young people.

6. Pharmacology and AU PBS notes

First-line: - Escitalopram (Lexapro, Cipralex) 10 to 20 mg orally daily. PBS listed for anxiety disorders under streamlined authority. Initial dose 5 mg for two weeks to minimise early activating side effects. - Sertraline (Zoloft) 50 to 200 mg orally daily. PBS listed. Often preferred given broad evidence base and tolerability profile. - Venlafaxine XR (Effexor XR) 75 to 225 mg orally daily. SNRI; PBS listed. Effective for comorbid depression. Discontinuation syndrome risk; taper slowly. - Duloxetine (Cymbalta) 60 to 120 mg orally daily. PBS listed for GAD. Also useful where comorbid painful somatic symptoms are present.

Second-line: - Buspirone 15 to 30 mg orally daily in divided doses. Non-benzodiazepine anxiolytic; no dependence risk; onset two to four weeks. Not PBS listed for GAD in Australia; may require private prescription or authority. - Pregabalin 150 to 600 mg orally daily in divided doses. Effective for GAD; PBS listed under Authority Required (streamlined) for neuropathic pain but not specifically for anxiety in AU; often prescribed off-label for GAD. Dependence and diversion risk exist.

Benzodiazepines (adjunctive, short-term only): - Diazepam (Valium) 2 to 5 mg two to three times daily. Corrected 2026-09-22, the taper timeframe was wrong. This note previously said "tapering over two to four weeks". The captured eTG chapter's deprescribing schedule is a gradual dose reduction over several months, reducing the dosage by approximately 25% of the original dose every 1 to 4 weeks, with slower weaning for the final dose reductions or if problematic discontinuation symptoms occur. It also advises seeking specialist advice when deprescribing a long-term benzodiazepine, considering a switch to a long-acting benzodiazepine such as diazepam before deprescribing, maintaining regular contact with the treating clinician, and using psychosocial interventions for residual anxiety. eTG's schedule is now used here. - Oxazepam 15 to 30 mg two to three times daily; not carried by the captured eTG chapter: the claim that oxazepam is preferred in the elderly because of a lack of active metabolites, and the doses for diazepam and oxazepam. eTG names only diazepam, and only as the long-acting option to switch to before deprescribing; it does not name oxazepam or lorazepam, and it does not rank agents by age. What eTG does say about older patients is that they should be assessed for frailty and comorbidity and may require doses lower than the recommended range. - PBS: benzodiazepines are general schedule items; Real-Time Prescription Monitoring (RTPM) is active nationally via SafeScript and equivalent state systems; repeat prescriptions require documented clinical review. Not carried by the captured eTG chapter: the PBS and RTPM statements. eTG's equivalent safeguard is to check a prescribing register or prescription monitoring service when assessing misuse risk. - Not carried by the captured eTG chapter: all of the escitalopram, sertraline, venlafaxine, duloxetine, buspirone and pregabalin doses and PBS statements above. The capture is an overview and does not give drug doses or PBS detail for any agent; genericised anxiety disorder is a separate related topic that is not captured.

Note on elderly patients: Benzodiazepines increase fall and fracture risk in older Australians; use the lowest effective dose and review regularly. Oxazepam and lorazepam are preferred over long-acting agents such as diazepam in this population.

7. Complications and monitoring

Complications: - Comorbid major depressive disorder occurs in over 60% of patients with GAD and substantially worsens prognosis; screen at every review using the PHQ-9. Not carried by the captured eTG chapter: the 60% figure and the PHQ-9 instruction. eTG records the general point that anxiety symptoms can be secondary to other psychiatric disorders such as major depression, and that comorbidity between anxiety disorders, mood disorders and problem substance use is frequent. - Substance use disorder, particularly alcohol and benzodiazepine dependence, is a common complication given their short-term anxiolytic effects. - Social and occupational impairment, relationship dysfunction, and reduced quality of life are significant long-term sequelae. - Suicidal ideation is elevated in GAD, particularly when comorbid depression is present; risk assessment is mandatory at each review. - Long-term benzodiazepine use is associated with cognitive impairment, tolerance, physical dependence, and rebound anxiety on cessation.

Monitoring schedule: - Initial medication review at two to four weeks to assess tolerability and early response. - Formal response assessment at six to eight weeks using GAD-7. - If response is partial at eight to twelve weeks, optimise dose before switching agent. - Once remission is achieved, continue pharmacotherapy for at least twelve months before considering a supervised taper to reduce relapse risk. - Annual review of ongoing benzodiazepine prescriptions with documented justification; cease if on long-term use and alternative treatments have not been trialled. - Monitor weight, blood pressure, and metabolic parameters annually given comorbidity with depression and antidepressant use. - Assess and document suicidality and functional status at every review.

Written for Australian practice and grounded in the guidance named above. Study material only — not medical advice. Always check against current guidelines.