Restlessness in suboccipital muscles as a manifestation of akathisia
Correspondence address: ShigehiroHirose MD Center of Psychiatry and Neurology, Fukui Prefectural Hospital, 2-12-1 Yotsui Fukuishi, Fukui 910-0846, Japan. Email: firstname.lastname@example.org
Abstract Antipsychotic-induced akathisia is primarily manifested as restlessness, particularly expressed in the legs. Consequently, rating scales and the research criteria of DSM-IV regard restlessness in the legs as the major sign of akathisia, although it has been suggested that such restlessness may occur in other areas of the body. A case of antipsychotic-induced akathisia is reported where the region of inner restlessness (the subjective component) was identified in posterior cervical muscles. The patient was initially suspected to be experiencing somatic delusions and the dose of antipsychotic medication was increased. This did not improve the symptoms, and upon careful questioning about his head discomfort, the patient acknowledged that he felt an inner restlessness in the suboccipital muscles. The restlessness ceased with intramuscular biperiden and subsequent discontinuation of antipsychotic medication. This case suggests that subjective restlessness may occur in muscle groups that are not usually associated with akathisia. Thus, this report may assist clinicians in the diagnosis of akathisia that could be overlooked or misdiagnosed as somatic delusions or the worsening of the patient's psychosis.
Antipsychotic-induced akathisia is primarily manifested as restlessness, particularly expressed in the legs.1 Consequently, rating scales and the research criteria of DSM-IV regard restlessness in the legs as the major sign of akathisia, although it has been suggested that such restlessness may occur in other areas of the body such as the abdomen or the arms.2–6 However, because this restlessness is often more troubling to the patient than the symptoms would suggest, it has been assumed that there is a large subjective component to this condition.7 A case of antipsychotic-induced akathisia is reported where the region of inner restlessness (the subjective component) was identified in posterior cervical muscles.
A-51-year-old man with a 25-year history of schizophrenia came to Fukui Prefectural Hospital after a 2-month period without medication, complaining of insomnia. The patient was given 3 mg of risperidone and 2 mg of flunitrazepam. Gradually, the patient's insomnia improved. Two weeks after the initiation of his treatment, the patient easily became angry and complained of a discomfort in his head, saying that ‘his head teased him.’ The patient was initially suspected to be experiencing somatic delusions and the dose of risperidone was increased to 6 mg. However, this did not improve his irritability and head discomfort.
Upon careful questioning about his head discomfort, he acknowledged that he felt inner restlessness in the deep muscles of the (lower) back of the head and (upper) back of the neck (i.e. the suboccipital muscles). He had experienced the same symptoms previously, during antipsychotic treatments. He denied restlessness in his legs or other parts of the body. He mentioned that he rolled about on the bed and shook his head because of the inner restlessness until he fell asleep. The patient stated that when he turned his head around or bent his head back and forth vehemently, his restlessness briefly abated. In contrast, when he was ordered to keep his head still, the restlessness worsened. There were no signs of parkinsonism such as tremor, rigidity, and akinesia. The patient was given 5 mg of biperiden intramuscularly and 30 min later, he reported that his feeling of discomfort and restlessness had disappeared. The patient's medication was changed from 6 mg of risperidone to 75 mg of chlorpromazine, and 6 mg of biperiden p.o. was added daily. The subjective inner restless feeling reappeared the next day and continued. The inner restlessness in the neck and head and the patient's irritation completely ceased 3 days after 75 mg of chlorpromazine was withdrawn from his medication regimen.
The patient was diagnosed as having acute, antipsychotic-induced akathisia. This was based on: (i) his subjective inner restless sensations in the (lower) back of the head; (ii) his restless movements of the head; (iii) his course of antipsychotic medication; and (iv) his response to biperiden and the reduction, and subsequent extinction of these symptoms following the withdrawal of antipsychotic drugs. The patient reported a brief improvement in his sense of restlessness following the movement of his cervical muscles, and the worsening of that sensation when his muscles were kept still. This phenomenon is similar to that previously reported in akathisia where restlessness in the legs is decreased when patients move their legs and keeping the legs still produces a worsening of the restlessness.8
Dyskinesia or dystonic reaction may be ruled out in that abnormal movements such as shaking the head in this case was not due to involuntary dyskinetic movements or muscular tonic contractions but due to voluntary movements to relieve restlessness. Subjective inner restlessness in the muscles may also not be true in dyskinesia or dystonia. In addition, voluntary forceful exercise of the muscles was able to ameliorate the distress, which might not be true of dyskinesia or dystonia. Somatic delusions or the worsening of the patient's psychosis could be ruled out by the amelioration of the symptoms with anticholinergic drugs and the withdrawal of antipsychotic medication.
The symptoms in this case suggest that the restless feeling, related to the inactivity of affected muscles, may be the primary symptom of akathisia. This can lead to the patient's voluntary activation of the muscles, which is manifested as restless movements of the muscles, thereby reducing the restless feeling. The observable restless movements then are secondary to the symptom of restless feeling in muscles. There may be an individual threshold for tolerance of the subjective experience of akathisia, but once that threshold is reached voluntary restless movements are prompted in order to try and gain some respite. This may help explain why certain akathisia patients show little or fewer restless movements and why restless movements in akathisia patients decrease or cease when the patient is distracted or sleeping.5,9,10
This case suggests that subjective restlessness may occur in muscle groups that are not usually associated with akathisia. Thus, this report may assist clinicians in the diagnosis of akathisia that could be overlooked or misdiagnosed as somatic delusions or the worsening of the patient's psychosis.