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Akathisia and Movement Side-Effects of Psychotropics

Akathisia is inability to sit still. It was thought to be hysterical or neurasthenic symptom, or possibly of compulsive origin. Later authors considered that it had a psychological basis. Similar symptoms of restlessness occur in patients with idiopathic Parkinson's disease and post-encephalitic parkinsonism. Systematic studies in Parkinson's disease identified akathisia in 26% of patients.

Patients treated with antipsychotic drugs exhibited restless or rhythmic movements of the legs and feet "neuroleptic-induced akathisia"

CLINICAL FEATURES

Subjective Experience

Patients with akathisia describe a subjective sense of inner restlessness, mental unease, unrest or dysphoria which can be intense. Anxiety correlates with the intensity of the subjective experience of akathisia and the associated distress reported. Feelings of inner restlessness were associated with marked symptoms of dysphoria, namely tension, panic, irritability and impatience.

This is associated with feeling unable to keep still or an irresistible urge to move. The condition is least tolerable when patients are required to stand still, for example, when waiting in a queue or cooking in the kitchen. Tension and discomfort in limbs, with paraesthesiae and unpleasant pulling or drawing sensations in the muscles of the legs are less common.

Motor Features

The restless movements are rocking from foot to foot and walking on the spot when standing, and shuffling and tramping of the legs or swinging one leg on the other when sitting. Pacing rapidly up and down is a characteristic of severe akathisia, and in the worst cases, patients are unable to tolerate staying in any position for more than a few minutes. Trunk rocking and fidgety movements of the upper limbs may be seen although less typical.

Akathisia is essentially an abnormal subjective state. The signs of motor restlessness are not present in mild cases of acute akathisia : subjective akathisia. When the feelings of inner restlessness and dysphoria reach a certain level of intensity, the patient is driven to agitated, restless movement in an attempt to gain respite.ACUTE AKATHISIA

Akathisia can be a dose-related condition of acute onset. 85% of patients developing akathisia display symptoms within a week of reaching the maximum dose of prescribed drug.In drug-naïve, normal subjects, the condition may develop within an hour or less of a single dose of a neuroleptic.

Incidence

Prevalence for akathisia is 25%, including mild cases. Prevalence rates for akathisia have ranged from 3% to 49%.

Akathisia may be considered acute if it is of less than six months duration and has developed soon after starting antipsychotic medication or following an increase in dosage. The condition may also develop acutely if a patient is switched to a high-potency antipsychotic or if anticholinergic medication is withdrawn. CHRONIC AKATHISIA

Akathisia can also be a persistent problem. A prevalence of around one-third has been found in schizophrenic outpatients receiving maintenance neuroleptic treatment. The condition may develop after a relatively short exposure to antipsychotic medication. The condition developed after less than one year of drug treatment in around one-third of cases. Pseudo akathisia

Repetitive, restless movements similar to those observed with acute akathisia may be seen in patients in the absence of a reported sense of inner restlessness or a compulsion to move. The main motor feature is rocking from foot to foot while standing. The prevalence of pseudo akathisia was 12%, 18% and 5% in various studies.

Pseudo akathisia is more common in males and older patients, associated with higher scores on negative symptoms, and coexist with tardive dyskinesia. There is a suggestion that it may be a manifestation of tardive dyskinesia due to the non-dyskinetic restless movements and the choreiform movements of pseudo akathisia and tardive dyskinesia.

One hypothesis regards pseudo akathisia as an end-stage akathisia in which the subjective component has diminished. Another possibility is that patients with akathisia have learned to avoid the dysphoric experience of the condition by adopting a regime of repetitive movement. Alternatively, rocking from foot to foot in the absence of subjective restlessness may simply represent a stereotypy.

Tardive (withdrawal) akathisia

In patients receiving long-term antipsychotic medication, akathisia may appear when this is withdrawn or the dose reduced. It has been called 'tardive' akathisia, because it shares some pharmacological characteristics of tardive dyskinesia: being exacerbated or precipitated by reduction or discontinuation of antipsychotic medication, and improved, at least transiently, if medication is restarted or the dose increased.

Acute persistent akathisia

In some cases, chronic akathisia appears to represent the persistence of acute akathisia for longer than six months.