How is akathisia diagnosed?

How is Akathisia Diagnosed?

Akathisia is diagnosed clinically by identifying both subjective inner restlessness and objective motor restlessness in a patient with recent antipsychotic or dopamine antagonist exposure, ideally using a validated rating scale such as the Barnes Akathisia Rating Scale. 1

Clinical Diagnostic Criteria

The diagnosis requires three essential components:

1. Drug Exposure History

• Recent initiation or dose increase of antipsychotic medication (typical or atypical)
• Dopamine antagonists (including antiemetics like prochlorperazine, metoclopramide)
• Timing: Symptoms typically emerge within the first few days of starting medication or after dose escalation 1
• Less commonly: SSRIs/SNRIs can cause akathisia (25% incidence in one study) 2

2. Characteristic Clinical Features

Subjective component (what the patient reports):

• Severe inner restlessness or tension
• Inability to sit still or remain motionless
• Compelling urge to move
• Patients may describe feeling "locked in" or trapped in a "glass coffin" 3
• Often misinterpreted as anxiety or psychotic agitation 4

Objective component (what you observe):

• Pacing or inability to remain seated
• Repetitive movements: foot tapping, leg crossing/uncrossing, rocking while standing
• Fidgeting or shifting weight from foot to foot
• Physical agitation 4, 1

3. Exclusion of Alternative Causes

Rule out:

• Psychotic agitation or worsening psychosis
• Anxiety disorders
• Restless legs syndrome (RLS) - occurs primarily at night/rest, relieved by movement 5
• Neuroleptic-induced akathisia vs. neuroleptic malignant syndrome
• Peripheral neuropathy or vascular claudication 5

Validated Assessment Tools

Barnes Akathisia Rating Scale - Most widely used and validated 6, 2, 3

• Assesses both subjective distress and objective restlessness
• Provides severity grading

Simplified Short Instrument 7:

• Derived for emergency department use
• 100% sensitivity and 99.2% specificity compared to conventional criteria
• Facilitates rapid diagnosis in acute settings

Common Diagnostic Pitfalls

Why akathisia is frequently missed 8:

Patient factors:

• Mild severity with subtle symptoms
• Lack of obvious motor restlessness
• Patient unable to articulate inner restlessness (developmental issues in children, cognitive impairment)
• Restlessness in body parts other than legs
• Overshadowed by other psychiatric symptoms

Clinician factors:

• Over-emphasis on objective restlessness while ignoring subjective complaints
• Failure to systematically assess for akathisia during antipsychotic therapy
• Misattribution to psychotic agitation or anxiety 4
• Not considering akathisia in ambiguous cases

Systematic Assessment Approach

As a good practice point, systematically assess akathisia with a validated scale:

• Before starting antipsychotics (baseline)
• During dose titration
• At regular intervals during treatment 6

Key diagnostic questions to ask:

1. "Do you feel restless inside, like you can't sit still?"
2. "Do you have an urge to constantly move your legs or pace?"
3. "When did this feeling start in relation to your medication?"
4. "Does moving around provide any relief?"

Diagnostic Certainty Levels

The frequency and nature of clinical features determine diagnostic certainty 9:

• Definite: Clear subjective + objective restlessness with temporal relationship to drug
• Probable: Subjective or objective features present with drug exposure
• Possible: Ambiguous presentation requiring trial of treatment

Special Populations

Cognitively impaired patients 5: Look for:

• Rubbing or kneading legs, groaning while holding lower extremities
• Excessive motor activity: pacing, fidgeting, repetitive kicking, tossing in bed
• Foot tapping, rubbing feet together, cycling movements
• Inability to remain seated
• Symptoms worse during inactivity and in evening/night

Children and adolescents 4:

• May have difficulty communicating symptoms due to developmental issues
• Higher risk for extrapyramidal side effects than adults
• Requires careful observation and age-appropriate questioning

Diagnostic Confirmation

Therapeutic trial can aid diagnosis 3:

• Response to anticholinergics (procyclidine, biperiden) supports diagnosis
• 16/20 patients in one case series had full response to procyclidine
• Dose reduction of offending agent should improve symptoms if akathisia is present 4, 10, 11