Akathisia

Akathisia (IPA: /æ.kə.ˈθɪ.si.ə/) is a movement disorder^[5] characterized by a subjective feeling of inner restlessness accompanied by mental distress and an inability to sit still.^[6][4] Usually, the legs are most prominently affected.^[2] Those affected may fidget, rock back and forth, or pace,^[7] while some may just have an uneasy feeling in their body.^[2] The most severe cases may result in poor adherence to medications, exacerbation of psychiatric symptoms, and, because of this, aggression, violence, and/or suicidal thoughts.^[2] Akathisia is also associated with threatening behaviour and physical aggression in mentally disordered patients.^[8] However, the attempts to find potential links between akathisia and emerging suicidal or homicidal behaviour were not systematic and were mostly based on a limited number of case reports and small case series.^[9] Apart from these few low-quality studies, there is another more recent and better quality study (a systematic review from 2021)^[9] that concludes akathisia cannot be reliably linked to the presence of suicidal behaviour in patients treated with antipsychotic medication.^[9]

Antipsychotic medication, particularly the first generation antipsychotics, are a leading cause.^[4][7] Other agents commonly responsible for this side-effect may also include selective serotonin reuptake inhibitors, metoclopramide, and reserpine, though any medication listing agitation as a side effect may trigger it.^[2][10] It may also occur upon stopping antipsychotics.^[2] The underlying mechanism is believed to involve dopamine.^[2] When antidepressants are the cause, there is no agreement regarding the distinction between activation syndrome from akathisia.^[11] Akathisia is often included as a component of activation syndrome.^[11] However, the two phenomena are not the same since the former, namely antipsychotic-induced akathisia, suggests a known neuroreceptor mechanism (e.g., dopamine-receptor blockade).^[11] Diagnosis is based on the symptoms.^[2] It differs from restless leg syndrome in that akathisia is not associated with sleeping. However, despite a lack of historical association between restless leg syndrome and akathisia, this does not guarantee that the two conditions do not share symptoms in individual cases.^[2]

Treatment may include switching to an antipsychotic with a lower risk of the condition, if the akathisia was caused by an antipsychotic.^[2] The antidepressant mirtazapine has demonstrated benefit, but is also known to have caused akathisia in certain individuals.^[5] as well as diphenhydramine, trazodone, benzatropine, cyproheptadine, and beta blockers, particularly propranolol.^[2][4][12]

The term was first used by Czech neuropsychiatrist Ladislav Haškovec, who described the phenomenon in 1901 long before the discovery of antipsychotics, with drug-induced akathisia first being described in 1960.^[1] It is from Greek a-, meaning "not", and καθίζειν kathízein, meaning "to sit", or in other words an "inability to sit".^[2]