Perioperative Anxiety: Preoperative Assessment, Melatonin, Music Therapy, and Psychological Preparation — A Clinical Review

Perioperative anxiety — the constellation of fear, apprehension, and autonomic arousal experienced in anticipation of and surrounding a surgical procedure — is among the most prevalent psychological phenomena encountered in medical settings. Despite its ubiquity, perioperative anxiety is frequently underrecognized, undertreated, and dismissed as an expected and inconsequential response to surgery. This characterization is clinically inaccurate. Perioperative anxiety significantly alters surgical outcomes, pain trajectories, hemodynamic stability, anesthetic requirements, and long-term psychological recovery.

Estimates of clinically significant preoperative anxiety range from 40% to 80% of adult surgical patients, depending on the population studied, the measurement instrument used, and the threshold applied for clinical significance. A large meta-analysis by Matthias and Samarasekera (2012) reported a pooled prevalence of approximately 48% among adult elective surgical patients when using validated instruments with standard cutoffs. In pediatric populations, prevalence estimates are even higher, with up to 60–70% of children demonstrating significant preoperative distress. Certain subgroups carry disproportionate risk: patients undergoing cancer surgery, cardiac surgery, and procedures under regional anesthesia with awareness (e.g., cesarean section under spinal anesthesia) consistently report higher anxiety levels.

The clinical consequences of unmanaged perioperative anxiety are measurable and consequential. Elevated preoperative anxiety is associated with increased intraoperative anesthetic requirements (by 20–30% for propofol induction doses in some studies), greater postoperative analgesic consumption, higher postoperative pain scores, prolonged hospital stays, increased rates of postoperative nausea and vomiting (PONV), and elevated risk of chronic postsurgical pain development. Furthermore, perioperative anxiety is a well-established risk factor for the development of posttraumatic stress disorder (PTSD) following surgery, particularly after ICU stays, cardiac surgery, and emergency procedures, with reported incidence rates of surgery-related PTSD ranging from 5% to 20%.

Perioperative anxiety engages the same fundamental neural circuitry implicated in generalized threat processing, but the specific context of surgical anticipation produces a characteristic neurobiological profile that has both state and trait components.

Central Circuitry: The Amygdala-Prefrontal-Insular Network

The basolateral amygdala (BLA) serves as the primary hub for processing threat-related stimuli in the perioperative context. Sensory information related to the hospital environment — unfamiliar sounds, clinical smells, medical equipment, preoperative conversations about surgical risk — enters the BLA via thalamic and cortical pathways. The BLA integrates this information with stored associative memories (prior surgical experiences, medical traumas, vicarious learning from others' surgical narratives) and projects to the central nucleus of the amygdala (CeA), which orchestrates downstream autonomic, endocrine, and behavioral responses.

The bed nucleus of the stria terminalis (BNST) is particularly relevant to perioperative anxiety because it mediates sustained, anticipatory anxiety — the diffuse apprehension characteristic of waiting for surgery — as opposed to the phasic, acute fear response mediated primarily by the CeA. The BNST receives dense corticotropin-releasing factor (CRF) innervation and projects to the hypothalamus, locus coeruleus, and periaqueductal gray, driving the prolonged physiological arousal observed in patients during extended preoperative waits.

The anterior insular cortex generates interoceptive predictions about anticipated bodily states during and after surgery (pain, nausea, helplessness, loss of consciousness). Research by Paulus and Stein (2006) has demonstrated that heightened anterior insular reactivity is a trait marker for anxiety sensitivity — the fear of anxiety-related bodily sensations — which is a robust predictor of perioperative distress. The medial prefrontal cortex (mPFC) and ventrolateral prefrontal cortex (vlPFC) normally exert top-down inhibitory control over the amygdala via glutamatergic projections to GABAergic interneurons. Reduced prefrontal-amygdala connectivity, observed in trait-anxious individuals, impairs this regulatory capacity and contributes to disproportionate perioperative anxiety responses.

Neurotransmitter Systems

GABA-Benzodiazepine System: GABAergic inhibition via GABA_A receptors is the primary inhibitory mechanism in anxiety regulation. The α2/α3 subunit-containing GABA_A receptors in the amygdala and hippocampus are the primary mediators of the anxiolytic effects of benzodiazepines. Perioperative stress reduces GABAergic tone through cortisol-mediated downregulation of GABA_A receptor expression, creating a neurochemical substrate for heightened anxiety.

Serotonergic (5-HT) System: Serotonin modulates perioperative anxiety through multiple receptor subtypes. 5-HT_1A receptor activation in the raphe nuclei and hippocampus is anxiolytic, while 5-HT_2C receptor activation in the amygdala and prefrontal cortex is anxiogenic. Genetic polymorphisms in the serotonin transporter gene (5-HTTLPR) — particularly the short (s) allele — are associated with elevated amygdala reactivity to threatening stimuli and have been linked to greater preoperative anxiety in preliminary surgical genomics studies.

Noradrenergic System: The locus coeruleus (LC)-norepinephrine system drives the sympathetic arousal component of perioperative anxiety. CRF release from the amygdala activates the LC, producing tachycardia, hypertension, diaphoresis, and the subjective sense of physiological hyperarousal. This system is the target of α2-adrenergic agonists such as clonidine and dexmedetomidine, which are used as perioperative anxiolytics.

Melatonergic System: Melatonin acts on MT₁ and MT₂ receptors in the suprachiasmatic nucleus, hippocampus, and amygdala. MT₁ receptor activation in the amygdala reduces neuronal firing rates, contributing to anxiolysis. Additionally, melatonin modulates GABAergic transmission by acting as a positive allosteric modulator at GABA_A receptors, providing a mechanistic bridge between melatonergic and GABAergic anxiolytic pathways.

HPA Axis and Cortisol Dynamics

Perioperative anxiety activates the hypothalamic-pituitary-adrenal (HPA) axis, producing elevated cortisol levels that are measurable hours before surgery. Preoperative salivary cortisol levels correlate with anxiety scores (r = 0.30–0.50 across studies) and predict intraoperative hemodynamic instability and postoperative pain intensity. Chronic preoperative stress — as occurs with prolonged waiting times for cancer surgery — may produce HPA axis dysregulation characterized by flattened diurnal cortisol rhythms and impaired cortisol awakening response, patterns associated with poorer wound healing and immune function.

Systematic preoperative assessment of anxiety is essential for risk stratification and intervention planning, yet it remains inconsistently implemented in surgical pathways globally. Several validated instruments are available, each with distinct psychometric properties and clinical applications.

Primary Assessment Instruments

Amsterdam Preoperative Anxiety and Information Scale (APAIS): The APAIS is the most widely used purpose-built instrument for preoperative anxiety screening. It is a 6-item self-report scale with two subscales: anxiety (4 items) and information desire (2 items). A cutoff score of ≥11 on the anxiety subscale identifies clinically significant preoperative anxiety with a sensitivity of approximately 82% and specificity of 68% against clinical interview. Its brevity makes it feasible for routine preoperative clinic use.

State-Trait Anxiety Inventory (STAI): The Spielberger STAI is the most extensively validated instrument in perioperative research. The State Anxiety (STAI-S) subscale measures transient, situational anxiety and is the most commonly used outcome measure in perioperative intervention trials. A score ≥40 (out of 80) is typically used to define clinically significant anxiety. The Trait Anxiety (STAI-T) subscale measures dispositional anxiety proneness and is the strongest single predictor of elevated preoperative state anxiety, with correlations of r = 0.50–0.65 in surgical populations.

Visual Analogue Scale for Anxiety (VAS-A): The VAS-A is a single-item measure on a 0–100 mm scale. While less psychometrically robust than multi-item instruments, its simplicity enables repeated real-time assessment (e.g., in the preoperative holding area). A cutoff of ≥30 mm shows reasonable sensitivity for clinically significant anxiety.

Hospital Anxiety and Depression Scale (HADS): The HADS is frequently used to assess both anxiety (HADS-A) and depression (HADS-D) in perioperative settings. A HADS-A score ≥8 identifies possible anxiety, and ≥11 indicates probable clinical anxiety. The HADS is particularly useful for identifying comorbid depression, which is present in approximately 20–30% of patients with high preoperative anxiety.

Risk Stratification: Identifying High-Risk Patients

Evidence consistently identifies the following risk factors for elevated perioperative anxiety:

• Female sex: Women report higher preoperative anxiety than men across nearly all studies, with effect sizes typically in the range of d = 0.30–0.50. This likely reflects both biological factors (hormonal modulation of amygdala reactivity) and sociocultural factors (differential socialization around emotional expression).
• Younger age: Anxiety tends to be higher in younger adults (18–40 years) compared to older adults, possibly reflecting greater uncertainty about surgical outcomes and less experience with medical procedures.
• Prior negative surgical or anesthetic experiences: Previous intraoperative awareness, severe postoperative pain, or perioperative complications are potent sensitizing events.
• Pre-existing anxiety disorders: Patients with generalized anxiety disorder (GAD), panic disorder, or specific phobias (especially blood-injection-injury phobia, which has a population prevalence of approximately 3–4%) are at markedly elevated risk.
• Low perceived information adequacy: Patients who feel inadequately informed about their procedure, anesthesia, and expected recovery course consistently report higher anxiety.
• Cancer surgery: The additional existential threat associated with cancer diagnosis elevates anxiety beyond the level attributable to the surgical procedure alone.
• High pain catastrophizing scores: Pain catastrophizing, measured by the Pain Catastrophizing Scale (PCS), predicts both preoperative anxiety and the transition from acute to chronic postsurgical pain.

Differential Diagnosis

Clinicians must distinguish perioperative anxiety from several conditions that may present similarly in the preoperative setting:

• Preoperative delirium prodrome: Particularly in elderly patients, agitation and apprehension may represent emerging delirium due to metabolic derangement, medication effects, or infection rather than anxiety.
• Substance withdrawal: Alcohol, benzodiazepine, and opioid withdrawal can produce anxiety, tachycardia, and diaphoresis that mimic perioperative anxiety. A thorough substance use history is essential.
• Thyrotoxicosis or pheochromocytoma: Endocrine conditions producing catecholamine excess should be considered when anxiety symptoms are accompanied by refractory tachycardia or hypertension.
• Panic disorder: Discrete panic attacks in the preoperative period may be misattributed to situational anxiety. The presence of catastrophic cognitions about bodily sensations (e.g., fear of dying during anesthesia) and a history of recurrent unexpected panic attacks suggests an underlying panic disorder requiring specific treatment.

Melatonin (N-acetyl-5-methoxytryptamine) has emerged as a compelling alternative to benzodiazepines for preoperative anxiolysis. Its favorable side-effect profile — absence of respiratory depression, minimal cognitive impairment, and lack of dependence potential — makes it particularly attractive in the perioperative context.

Pharmacology and Anxiolytic Mechanisms

Melatonin's anxiolytic effects are mediated through multiple mechanisms:

• MT₁ and MT₂ receptor agonism: MT₁ receptors in the suprachiasmatic nucleus promote sleep onset and reduce arousal. MT₂ receptors in the hippocampus and amygdala modulate anxiety-related neuronal firing. Knockout studies in rodents confirm that MT₂ receptor deletion increases anxiety-like behavior.
• GABAergic potentiation: Melatonin enhances GABA_A receptor function, likely through allosteric modulation, increasing chloride conductance and neuronal inhibition in the amygdala and cortex.
• Modulation of the HPA axis: Melatonin attenuates CRF release and reduces cortisol secretion, counteracting the HPA axis hyperactivation characteristic of perioperative stress.
• Antioxidant and anti-inflammatory properties: Melatonin scavenges reactive oxygen species and modulates inflammatory cytokine release (IL-6, TNF-α), which may contribute to its broader perioperative benefits including reduced postoperative pain.

Efficacy Data: Meta-Analytic Evidence

The landmark Cochrane review by Hansen et al. (2015) — "Melatonin for pre- and postoperative anxiety in adults" — analyzed 12 randomized controlled trials (RCTs) involving 774 participants. Key findings included:

• Melatonin significantly reduced preoperative anxiety compared to placebo, with a standardized mean difference (SMD) of −0.40 (95% CI: −0.59 to −0.21), representing a moderate effect.
• When compared directly to midazolam, melatonin showed comparable anxiolytic efficacy (no statistically significant difference in 6 head-to-head trials), with an SMD of −0.08 (95% CI: −0.31 to 0.16), indicating non-inferiority.
• Melatonin was associated with significantly less psychomotor impairment and sedation than midazolam, a critical advantage for ambulatory surgery patients who require rapid cognitive recovery.
• Melatonin did not produce anterograde amnesia, in contrast to midazolam, which produces dose-dependent amnesia — a property that may mask rather than treat distress.

A subsequent meta-analysis by Yousaf et al. (2018) confirmed these findings and additionally reported that melatonin reduced postoperative anxiety scores, an effect not consistently observed with midazolam. This suggests that melatonin's anxiolytic mechanism differs qualitatively from benzodiazepine-induced sedation and amnestic effects.

Dosing Considerations

Optimal dosing for preoperative anxiolysis has not been definitively established, but the majority of positive trials have used doses between 3 mg and 10 mg administered orally 60–120 minutes before surgery. Some evidence suggests a dose-response relationship, with 5 mg outperforming 3 mg in anxiety reduction. Sublingual formulations may offer faster onset due to bypassing first-pass hepatic metabolism. Of note, melatonin's bioavailability is highly variable (approximately 15% on average with oral administration), contributing to heterogeneity across trials.

Limitations

Several limitations temper enthusiasm for melatonin as a first-line perioperative anxiolytic: substantial heterogeneity across trials in dosing, timing, surgical populations, and outcome measures; the absence of large, definitive multicenter RCTs; uncertain efficacy in patients with severe preoperative anxiety (most trials enrolled patients with moderate anxiety levels); and lack of standardized pharmaceutical formulations in many countries (melatonin is sold as a dietary supplement in the United States, with variable quality control).

Music-based interventions represent the most extensively studied non-pharmacological approach to perioperative anxiety, with a robust evidence base supporting their efficacy across diverse surgical populations and settings.

Neurobiological Mechanisms

Music modulates anxiety through several overlapping neural pathways:

• Autonomic nervous system regulation: Slow-tempo music (60–80 beats per minute) entrains heart rate through auditory-cardiac coupling, promoting parasympathetic dominance via vagal activation. This reduces tachycardia, lowers blood pressure, and decreases circulating catecholamine levels.
• Dopaminergic reward activation: Pleasurable music activates the nucleus accumbens and ventral tegmental area (VTA), releasing dopamine that counteracts the aversive emotional state produced by amygdalar threat processing. Salimpoor et al. (2011) demonstrated using PET imaging that peak pleasurable responses to music are associated with dopamine release in the striatum.
• Cortisol suppression: Multiple studies demonstrate that perioperative music listening reduces salivary cortisol levels by approximately 15–25% relative to standard care.
• Attentional gating: Music engages auditory cortex, prefrontal regions, and default mode network resources, competing with and partially displacing threat-related cognitive processing (worry, catastrophizing). This represents an external attentional refocusing mechanism analogous to distraction techniques in cognitive-behavioral therapy.
• Endogenous opioid release: Evidence suggests that music listening activates endogenous opioid systems, which may contribute to both anxiolytic and analgesic effects. Naloxone administration partially blocks music-induced analgesia, supporting opioidergic involvement.

Meta-Analytic Evidence

The most comprehensive meta-analysis in this field is the Cochrane review by Bradt, Dileo, and Shim (2013, updated 2016), which analyzed 26 RCTs involving over 2,000 surgical patients. Key findings:

• Music interventions significantly reduced preoperative anxiety with an SMD of −0.69 (95% CI: −0.95 to −0.43), a moderate-to-large effect exceeding that observed for melatonin.
• Music significantly reduced heart rate (mean reduction of 4.59 bpm, 95% CI: −6.29 to −2.89) and systolic blood pressure (mean reduction of 4.49 mmHg).
• Effects were robust across surgical subtypes, including cardiac, orthopedic, gynecological, and ambulatory procedures.
• Patient-selected music was more effective than researcher-selected music, consistent with the role of personal preference and perceived control in the anxiolytic mechanism.

A further meta-analysis by Fu et al. (2020) confirmed that perioperative music reduced both state anxiety (STAI-S) and physiological stress markers, with the number needed to treat (NNT) for a clinically meaningful anxiety reduction (≥10-point decrease on STAI-S) estimated at approximately 4–5.

Music Therapy vs. Music Medicine

A clinically important distinction exists between music therapy (a clinical intervention delivered by a board-certified music therapist involving active music-making, improvisation, or structured therapeutic interaction) and music medicine (passive listening to pre-recorded music, typically delivered via headphones without a therapist). Both are effective, but music therapy delivered by a credentialed therapist generally produces larger effect sizes. However, the scalability and cost-effectiveness of music medicine (headphone-based listening) makes it far more feasible for routine perioperative implementation.

Implementation Considerations

Evidence-based implementation guidelines recommend:

• Music with a tempo of 60–80 bpm, preferably instrumental, with minimal dynamic variation
• Patient choice of music genre when possible
• Minimum duration of 15–30 minutes, initiated at least 30 minutes before surgery
• Use of noise-canceling headphones to reduce environmental auditory stressors
• Continuation into the intraoperative period (for procedures under regional anesthesia or sedation) and into the postoperative recovery area

Psychological preparation for surgery encompasses a heterogeneous group of interventions that target the cognitive, emotional, and behavioral dimensions of perioperative anxiety through structured, evidence-based protocols.

Procedural and Sensory Information Provision

The foundational work by Janis (1958) on the "work of worrying" established that patients given detailed preparatory information experience less postoperative distress than those given either no information or excessive information. This observation has been refined into the distinction between procedural information (what will happen) and sensory information (what the patient will feel, see, hear, and smell). Sensory information is consistently more effective at reducing anxiety than procedural information alone. A meta-analysis by Johnston and Vögele (1993) reported that combined procedural-sensory information reduced anxiety with an effect size of d = 0.40 and reduced postoperative pain with an effect size of d = 0.35.

However, not all patients benefit equally from information provision. The construct of monitoring vs. blunting coping style (Miller, 1987) predicts that "monitors" (patients who actively seek information when threatened) benefit from detailed information, while "blunters" (patients who prefer distraction and avoidance) may experience increased anxiety from excessive information. The APAIS information subscale can serve as a practical screen for information-seeking preference.

Cognitive-Behavioral Interventions (CBIs)

Cognitive-behavioral approaches to perioperative anxiety target maladaptive cognitions — catastrophic misinterpretations of surgical risk, overestimation of pain intensity, and beliefs about loss of control — through structured techniques:

• Cognitive restructuring: Identification and modification of catastrophic surgical cognitions (e.g., "I will die under anesthesia" → "Anesthesia-related mortality in healthy patients is approximately 1 in 100,000–200,000").
• Relaxation training: Progressive muscle relaxation (PMR), diaphragmatic breathing, and guided imagery. PMR has been shown to reduce preoperative STAI-S scores by approximately 8–12 points in controlled trials.
• Guided imagery: Structured visualization of successful surgery and positive recovery. A systematic review by Gonzales et al. (2010) reported moderate effect sizes (d = 0.42) for guided imagery on preoperative anxiety.

A meta-analysis by Powell et al. (2016) examining psychological preparation for surgery across 105 studies found that psychological interventions produced significant reductions in preoperative anxiety (SMD = −0.35), postoperative pain (SMD = −0.20), length of hospital stay (mean reduction of 0.52 days), and negative postoperative behavioral outcomes. The overall quality of evidence was moderate, with significant heterogeneity in intervention type, dose, and delivery format.

Mindfulness-Based Interventions

Brief mindfulness-based interventions (MBIs) — typically involving 10–20 minutes of guided mindfulness meditation focused on present-moment awareness and non-judgmental acceptance of anxious thoughts and sensations — represent a newer approach with growing evidence. A meta-analysis by Dhillon et al. (2022) examined 15 RCTs and reported a significant anxiolytic effect with an SMD of −0.55 (95% CI: −0.83 to −0.26). Mindfulness interventions appear particularly well-suited to perioperative anxiety because they directly target anticipatory worry (future-oriented threat cognitions) by redirecting attention to present-moment experience.

Virtual Reality (VR) Distraction

Immersive VR is an emerging modality for preoperative anxiety management. VR provides multisensory distraction that engages visual, auditory, and proprioceptive processing, effectively competing with threat-related neural activity. Early RCTs suggest anxiety reductions of 30–50% on VAS-A compared to standard care, with effect sizes comparable to or exceeding pharmacological anxiolysis. The technology remains cost-prohibitive for widespread implementation, but decreasing hardware costs are rapidly improving feasibility.

Direct head-to-head comparisons across pharmacological and non-pharmacological perioperative anxiety interventions remain relatively uncommon, but available evidence allows preliminary comparative effectiveness conclusions.

Effect Size Comparisons

Based on available meta-analytic data, the approximate effect sizes for anxiety reduction (preoperative STAI-S or equivalent) are:

• Midazolam (1–5 mg oral/IV): SMD ≈ −0.50 to −0.70 vs. placebo. Highly effective for immediate anxiolysis but limited by sedation, cognitive impairment, anterograde amnesia, respiratory depression risk, and potential for paradoxical reactions (particularly in elderly patients and children).
• Melatonin (3–10 mg oral): SMD ≈ −0.40 vs. placebo. Comparable to midazolam for anxiolysis without cognitive impairment or respiratory depression. NNT estimated at approximately 5–7 for clinically meaningful anxiolysis.
• Music-based interventions: SMD ≈ −0.69 vs. standard care. The largest effect among non-pharmacological interventions. NNT estimated at approximately 4–5. No adverse effects. Highly scalable.
• Psychological preparation (combined): SMD ≈ −0.35 vs. standard care. More modest acute anxiolytic effect but unique advantages in reducing postoperative pain, length of stay, and long-term psychological outcomes.
• Mindfulness-based interventions: SMD ≈ −0.55 vs. standard care. Promising but evidence base is more limited than for music or pharmacological interventions.
• Dexmedetomidine (intranasal or IV): SMD ≈ −0.60 to −0.80 vs. placebo. Effective α2-agonist anxiolytic with analgesic-sparing properties but requires monitoring and is typically restricted to anesthesiologist-supervised settings.

Multimodal Approaches

Emerging evidence supports the superiority of multimodal anxiolytic strategies — combining pharmacological and non-pharmacological interventions — over monotherapy. For example, combining music listening with melatonin premedication may produce additive anxiolytic effects through complementary neurobiological mechanisms (GABAergic/melatonergic enhancement plus autonomic-cortical modulation). However, rigorous factorial trials testing specific multimodal combinations are largely lacking and represent a major research gap.

Enhanced Recovery After Surgery (ERAS) Integration

ERAS protocols, which have transformed perioperative care across surgical specialties, increasingly incorporate anxiety management as a core component. The ERAS Society guidelines recommend preoperative counseling and information provision as standard elements. However, specific pharmacological and non-pharmacological anxiolytic interventions are not yet consistently included in ERAS protocols, representing an implementation gap. Integrating validated anxiolytic strategies into ERAS pathways has the potential to improve both patient experience and surgical outcomes.

Perioperative anxiety does not occur in isolation. Understanding comorbidity patterns is essential for effective assessment and treatment planning.

Pre-Existing Anxiety Disorders

Patients with pre-existing anxiety disorders — present in approximately 15–20% of the adult population at any given time (NIMH estimates) — are at markedly elevated risk for severe perioperative anxiety. Generalized anxiety disorder (GAD) is the most common comorbidity, present in an estimated 8–12% of surgical patients. Patients with GAD have baseline trait anxiety levels that amplify state anxiety responses to surgical threat, often resulting in STAI-S scores >55 preoperatively. Panic disorder patients may experience perioperative panic attacks triggered by physiological sensations of IV insertion, monitoring equipment, or the sensation of "losing control" during anesthetic induction.

Depression

Comorbid depression is present in approximately 20–30% of patients with clinically significant preoperative anxiety. The combination of anxiety and depression is particularly concerning because it predicts:

• Greater postoperative pain intensity and analgesic consumption
• Longer hospital stays (approximately 1–2 additional days on average)
• Higher rates of surgical site infections (possibly mediated by immune suppression via HPA axis dysregulation)
• Increased risk of postoperative delirium in elderly patients (OR ≈ 2.0–3.0)
• Greater risk of chronic postsurgical pain development (OR ≈ 2.5)

Pain Catastrophizing

Pain catastrophizing — characterized by rumination about pain, magnification of its threat value, and perceived helplessness — is a cognitive-affective construct that overlaps with but is distinct from anxiety. Approximately 20–30% of surgical patients score above clinical thresholds on the Pain Catastrophizing Scale. High pain catastrophizing is the strongest psychological predictor of acute postoperative pain intensity (explaining 7–31% of variance across studies) and the transition to chronic postsurgical pain.

Prior Trauma and PTSD

A history of psychological trauma — particularly medical trauma, sexual assault (relevant for gynecological and urological procedures), or childhood abuse — significantly amplifies perioperative anxiety. Patients with PTSD may experience trauma re-activation during procedures that involve physical restraint, loss of consciousness, exposure, or physical vulnerability. Prevalence of prior trauma history in surgical populations is estimated at 25–40%, though it is often unscreened.

Substance Use Disorders

Patients with active or recent substance use disorders (approximately 8–10% of surgical populations in Western settings) present dual challenges: elevated baseline anxiety, and the risk of withdrawal syndromes being misattributed to situational perioperative anxiety. Additionally, benzodiazepine tolerance in patients with alcohol or benzodiazepine use disorders renders standard pharmacological anxiolysis ineffective, necessitating alternative approaches such as melatonin or dexmedetomidine.

Several factors predict the trajectory and treatment responsiveness of perioperative anxiety.

Favorable Prognostic Indicators

• Low trait anxiety: Patients with STAI-T scores <40 typically respond well to brief interventions (information provision, single-session relaxation training, or music listening alone).
• High information-seeking coping style: "Monitors" who actively engage with preparatory information show robust anxiety reduction with structured preoperative education programs.
• Adequate perceived social support: Patients who feel supported by family, friends, and clinical staff report lower preoperative anxiety and better postoperative adjustment.
• Prior positive surgical experiences: Positive surgical memories provide a safety signal that attenuates amygdalar threat processing for subsequent procedures.
• Self-efficacy for coping: Patients who believe they can manage their anxiety and cope with recovery demands (high surgical self-efficacy) have better outcomes.

Poor Prognostic Indicators

• High trait anxiety (STAI-T >50): Trait-anxious individuals may require multimodal interventions (combined pharmacological and psychological) and are less likely to respond to single-component interventions.
• Pain catastrophizing (PCS >30): Predicts both elevated perioperative anxiety and poor postoperative pain outcomes. Specific cognitive-behavioral interventions targeting catastrophizing are recommended.
• History of intraoperative awareness: One of the most potent predictors of severe preoperative anxiety for subsequent surgeries. May require specific psychoeducation about bispectral index (BIS) monitoring and anesthetic depth assurance.
• Comorbid depression: Depressed patients show blunted responses to brief anxiolytic interventions and require more intensive, longer-duration preparation.
• Prolonged preoperative waiting time: Extended waits between cancer diagnosis and surgery are associated with progressive anxiety escalation and HPA axis dysregulation.
• Pediatric age group: Children, particularly ages 2–7, show the highest rates of preoperative anxiety and behavioral distress. Parental anxiety is the strongest modifiable predictor of child perioperative anxiety, creating a dyadic treatment target.

Perioperative anxiety management must be adapted to the unique needs of specific populations.

Pediatric Patients

Preoperative anxiety in children is associated with negative postoperative behavioral changes — including new-onset separation anxiety, sleep disturbances, enuresis, and temper tantrums — occurring in 40–60% of children following surgery. The modified Yale Preoperative Anxiety Scale (mYPAS) is the gold-standard observational measure for pediatric preoperative anxiety. Key evidence-based interventions include:

• Parental presence at induction (PPIA): Effective when parents are coached and calm, but can be counterproductive if the parent is highly anxious. A meta-analysis found no overall benefit of PPIA without parental preparation.
• Child life specialist involvement: Medical play, therapeutic preparation, and developmentally appropriate information significantly reduce preoperative distress.
• Midazolam premedication (0.5 mg/kg oral): Remains the pharmacological standard. Melatonin (0.1–0.5 mg/kg) shows promise as an alternative with less postoperative behavioral disruption, though evidence is less robust than in adults.
• Clown therapy and interactive distraction: Multiple RCTs demonstrate that clown doctors and tablet-based interactive games reduce preoperative anxiety to a degree comparable to midazolam premedication.

Geriatric Patients

Older adults (≥65 years) present unique challenges: higher rates of cognitive impairment limiting self-report assessment validity, greater sensitivity to benzodiazepine adverse effects (falls, delirium, paradoxical agitation), and the confounding overlap between anxiety and delirium prodrome. Melatonin is particularly attractive in this population because it may simultaneously reduce anxiety and delirium incidence — the MENDS trial and related studies have suggested that exogenous melatonin reduces ICU delirium rates, though evidence is not yet definitive. Non-pharmacological approaches (music listening, structured information provision, familiar object provision) should be prioritized.

Surgical Oncology

Cancer surgery patients carry a dual burden of surgical anxiety and cancer-related existential distress. Preoperative anxiety prevalence in cancer surgery populations exceeds 60%, with rates of clinical-level anxiety and depression reaching 30–40% in some series. Waiting time between diagnosis and surgery is a particularly potent anxiety amplifier. Psychological preparation programs that address both surgical and oncological concerns — including prognostic uncertainty, body image changes, and fears of recurrence — are more effective than generic surgical preparation in this population.

Despite substantial progress, the field of perioperative anxiety management faces several significant evidence gaps and emerging research frontiers.

Key Limitations of Current Evidence

• Outcome measurement heterogeneity: Trials use different instruments (STAI, VAS, APAIS, HADS), different measurement time points (preoperative clinic, holding area, induction), and different thresholds for clinical significance, limiting cross-study comparability and meta-analytic precision.
• Lack of long-term outcome assessment: Most trials assess anxiety only in the immediate preoperative period. Very few studies track downstream outcomes including chronic postsurgical pain, PTSD, quality of life, or healthcare utilization.
• Absence of large, pragmatic, multicenter trials: The majority of studies are single-center, moderate-sample trials. Definitive evidence requires large pragmatic trials embedded in real-world surgical pathways.
• Inadequate reporting of comorbidity: Most trials exclude or fail to report on patients with pre-existing psychiatric disorders, the very population most vulnerable to severe perioperative anxiety.
• Limited cost-effectiveness data: The economic argument for perioperative anxiety management — reduced length of stay, fewer complications, decreased analgesic consumption — is compelling but has not been rigorously quantified across interventions.

Emerging Research Directions

• Precision perioperative mental health: The vision of tailoring anxiolytic interventions to individual patient profiles — based on trait anxiety levels, coping style, genetic polymorphisms (e.g., 5-HTTLPR, COMT Val158Met), and physiological biomarkers (heart rate variability, cortisol) — is a major frontier. Machine learning algorithms applied to preoperative data may enable predictive risk stratification with greater accuracy than current screening instruments.
• Digital health interventions: Smartphone-based applications delivering guided relaxation, mindfulness exercises, and psychoeducation in the days before surgery represent a scalable, low-cost approach. Several apps are currently being evaluated in RCTs.
• Perioperative ketamine: Sub-anesthetic ketamine, through its NMDA receptor antagonism and rapid antidepressant effects, is being explored not only for perioperative analgesia but also for perioperative anxiety and depression, particularly in cancer surgery patients.
• Psychedelic-assisted preparation: Very early-phase research is exploring whether psilocybin-assisted therapy — which has demonstrated remarkable efficacy for existential distress in terminal cancer patients in trials at Johns Hopkins and NYU — could be applied to preoperative existential anxiety in cancer surgery patients. This remains highly exploratory.
• Neuroimaging-based prediction: Functional connectivity patterns between the amygdala, insula, and prefrontal cortex, assessed via resting-state fMRI, may predict individual vulnerability to perioperative anxiety and treatment response, though this approach is not yet clinically feasible.

Based on the available evidence, the following clinical recommendations are supported:

• Universal screening: All patients presenting for elective surgery should be screened for preoperative anxiety using a validated instrument (APAIS or STAI-S). Screening should occur at the preoperative assessment visit and again in the preoperative holding area.
• Risk stratification: Patients scoring above clinical thresholds, those with pre-existing anxiety or mood disorders, prior traumatic surgical experiences, or high pain catastrophizing should be flagged for intensified intervention.
• Graduated intervention: A stepped-care model is recommended: Step 1 — structured sensory and procedural information provision for all patients; Step 2 — music-based intervention and/or brief relaxation training for patients with moderate anxiety; Step 3 — pharmacological anxiolysis (melatonin first-line, benzodiazepines for refractory cases) and/or referral for psychological preparation for patients with severe or comorbid anxiety.
• Melatonin over benzodiazepines when feasible: Melatonin (5–10 mg, 60–90 minutes preoperatively) should be considered as a first-line pharmacological option, particularly in ambulatory, geriatric, and pediatric populations where benzodiazepine adverse effects are most consequential.
• Multimodal integration: The combination of non-pharmacological (music, psychological preparation) and pharmacological (melatonin, low-dose dexmedetomidine) approaches is likely superior to monotherapy, though definitive evidence is awaited.
• ERAS pathway integration: Anxiety management should be embedded as a standard component of Enhanced Recovery After Surgery protocols across all surgical specialties.
• Training and implementation science: Surgical and anesthesia teams require training in anxiety recognition, screening instrument use, and delivery of brief psychological interventions. Implementation science research is needed to identify optimal strategies for embedding anxiety management into routine perioperative workflows.