What is akathisia?

What is Akathisia

Akathisia is a drug-induced movement disorder characterized by severe inner restlessness and an overwhelming urge to move, most commonly caused by antipsychotic medications that block dopamine D2 receptors. 1

Clinical Presentation

Akathisia manifests through both subjective and objective components that distinguish it from other psychiatric symptoms:

Subjective Features

• Patients experience an intense feeling of inner restlessness and an irresistible urge to move 1, 2
• Severe dysphoria and subjective distress frequently accompany the motor restlessness 2, 3

Objective Features

• Observable motor manifestations include pacing, rocking while standing or sitting, lifting feet as if marching on the spot, and repeatedly crossing and uncrossing legs while seated 2
• Fidgety movements and the inability to sit or stand still for extended periods are characteristic 4

Classification by Timing

Akathisia can be categorized based on when it develops during antipsychotic treatment:

• Acute akathisia occurs during the initial phases of treatment, typically within the first few days to weeks after starting medication or increasing the dose 1, 5
• Tardive akathisia develops after prolonged antipsychotic use, typically after months or years of treatment 2
• Withdrawal akathisia emerges when antipsychotics are discontinued 2
• Chronic akathisia persists despite ongoing treatment adjustments 2

Causative Medications

While most commonly associated with antipsychotics, akathisia can be induced by multiple drug classes:

• High-potency conventional antipsychotics (e.g., haloperidol) carry the highest risk 1
• Second-generation antipsychotics including aripiprazole, cariprazine, lurasidone, brexpiprazole, and asenapine can induce akathisia, with cariprazine showing the highest incidence rate (17.2%) and iloperidone the lowest (3.9%) 6
• Even antipsychotics with minimal extrapyramidal side effects like clozapine, quetiapine, and olanzapine may cause akathisia 3
• SSRIs, SNRIs, stimulants, mirtazapine, and tetrabenazine have also been reported to cause akathisia 1, 3

Prevalence and Risk Factors

• Reported prevalence rates vary widely between 5% and 36.8% in patients treated with antipsychotics 2
• Children and adolescents may be at higher risk for akathisia compared to adults 1, 5
• The overall risk of akathisia with newer antipsychotics is more than two-fold higher compared to placebo (OR 2.43) 6

Critical Diagnostic Pitfall

Akathisia is frequently misinterpreted as psychotic agitation or anxiety, leading clinicians to inappropriately increase antipsychotic doses, which paradoxically worsens the condition. 1, 7, 5 This misdiagnosis is a common reason for medication noncompliance and can increase morbidity 1

Differential Diagnosis

Akathisia must be distinguished from several conditions:

• Peripheral neuropathies and radiculopathies 1
• Vascular disease (intermittent claudication) 1
• Arthritides and venous varicosities 1
• Psychotic agitation or anxiety (the most common misdiagnosis) 1, 7
• Restless legs syndrome (RLS), which has distinct diagnostic criteria including worsening at rest and relief with movement, but differs in its primary evening/nighttime occurrence and association with iron deficiency 1

Special Safety Consideration

SSRI-induced akathisia is associated with increased suicidality, particularly with fluoxetine, and clinicians must systematically inquire about suicidal ideation before and after treatment initiation. 7 The combination of akathisia and suicidal ideation represents a psychiatric emergency requiring immediate intervention 7

Pathophysiology

The exact mechanism remains incompletely understood, but akathisia is attributed to an imbalance between dopaminergic and noradrenergic neurotransmission in the basal ganglia 3