Akathisia
The physical exam finding of a patient moving as if stretching their muscles or dancing is characteristic of akathisia, a drug-induced movement disorder most commonly caused by antipsychotic medications. 1, 2
Clinical Presentation
Akathisia manifests with both subjective and objective components that distinguish it from other movement disorders:
Subjective symptoms:
- Inner restlessness and an overwhelming urge to move 3, 4
- Emotional unease and anxiety 4
- Inability to tolerate inactivity or remaining still 4
Objective motor findings:
- Pacing or restless walking 1, 2
- Rocking while standing or sitting 3
- Lifting feet as if marching on the spot 3
- Crossing and uncrossing legs while seated 3
- Repetitive foot tapping and rubbing feet together 5
- Physical agitation that resembles stretching or dancing movements 1
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, 2, 4 This misdiagnosis can result in poor medication adherence, exacerbation of psychiatric symptoms, and in severe cases, aggression, violence, and suicide. 6
Differential Diagnosis
The American Academy of Child and Adolescent Psychiatry emphasizes distinguishing akathisia from other conditions: 1
- Restless Legs Syndrome (RLS): Symptoms improve with movement like walking or stretching, worsen at night with circadian pattern, and primarily affect lower extremities with relief during activity 5
- Tardive Dyskinesia: Involuntary, rhythmic movements primarily affecting the orofacial region that develop after prolonged antipsychotic use (months to years) 1
- Drug-induced Parkinsonism: Bradykinesia, tremors, and rigidity without the subjective restlessness 1
- Acute Dystonia: Sudden spastic muscle contractions of neck, eyes, and torso 1
Causative Medications
The American Academy of Child and Adolescent Psychiatry identifies common culprits: 1, 2
- High-potency typical antipsychotics (highest risk) 1
- Atypical antipsychotics (lower but still present risk) 1
- SSRIs (particularly fluoxetine, associated with increased suicidality) 2
- Antiemetics and other dopamine-blocking agents 3
Assessment Approach
When akathisia is suspected, systematically inquire about the subjective feeling of inner restlessness and observe for characteristic repetitive movements, particularly noting if symptoms worsen after antipsychotic dose increases. 2, 4 The diagnosis is primarily clinical and does not require polysomnography or other objective testing in most cases. 5
Accelerometric recordings can demonstrate constant wave forms with frequency below 4 Hz and reproducible patterns, though this is not routinely necessary for diagnosis. 7
Risk Factors
Young age and male gender increase risk for acute extrapyramidal symptoms including akathisia. 1, 2 Children and adolescents have higher risk compared to adults. 2