Akathisia may range in intensity from a mild sense of disquiet or anxiety (which may be easily overlooked) to a total inability to sit still, accompanied by overwhelming anxiety, malaise, and severe dysphoria (manifesting as an almost indescribable sense of terror and doom). The condition is difficult for the patient to describe and is often misdiagnosed. When misdiagnosis occurs in antipsychotic neuroleptic-induced akathisia, more antipsychotic neuroleptics may be prescribed, potentially worsening the symptoms. High-functioning patients have described the feeling as a sense of inner tension and torment or chemical torture.
The presence and severity of akathisia can be measured using the Barnes Akathisia Scale.
Jack Henry Abbot (1981) described the effects of akathisia produced by antipsychotic drugs:
In severe cases, akathisia can be so tormenting that the patient is compelled to take action, such as suicide attempts.
Treatment non-compliance is a common consequence of neuroleptic-induced akathisia. At the extreme end of non-compliance, patients who have been treated with neuroleptic antipsychotics for psychotic episodes or prochlorperazine for nausea may rarely run away from hospitals or emergency rooms due to this disconcerting sensation.
The 2006 UK study by Healy, Herxheimer, and Menkes observed that akathisia is often miscoded in antidepressant clinical trials as "agitation, emotional lability, and hyperkinesis (overactivity)". The study further points out that misdiagnosis of akathisia as simple motor restlessness occurs, but that this is more properly classed as dyskinesia. Healy, et al., further show links between antidepressant-induced akathisia and violence, including suicide, as akathisia can "exacerbate psychopathology." The study goes on to state that there is extensive clinical evidence correlating akathisia with SSRI use, showing that approximately ten times as many patients on SSRIs as those on placebos showed symptoms severe enough to drop out of a trial (5.0% compared to 0.5%).
The most common treatment for antipsychotic akathisia is the anticholinergic medication benztropine (Cogentin). But since benztropine is for extrapyramidal side effects such as muscle spasms, muscle stiffness and tremors it is not effective in treating akathisia which is not a true extrapyramidal side effect. Other anticholinergic medications such as diphenhydramine may also be used in the treatment of akathisia.
Akathisia can be reduced by administering other drugs, though effectiveness can vary with more severe cases resistant to most drug treatment. Benzodiazepines like clonazepam (Klonopin) are effective. Some consider the drug of choice for the treatment of akathisia to be beta-blockers such as propranolol (Inderal) or metoprolol. The antihistamine cyproheptadine is also effective, though with shorter effect than beta blockers.
One study showed that vitamin B6 is effective for the treatment of neuroleptic-induced akathisia.