SSRI induced hypnic jerks: A case series

ABSTRACT

A hypnic jerk is an abrupt, involuntary, nonrepetitive contraction of muscles of the body that occurs during the onset of sleep in stage 1 of nonrapid eye movement sleep. Various physiological and stressful stimuli can precipitate hypnic jerks with no further neurological sequelae. Although selective serotonin reuptake inhibitor (SSRI) medications are well known to disturb the normal sleep cycle and cause rapid eye movement sleep behavioral disorders, there were only a few case reports of them causing hypnic jerks and those were reported due to Escitalopram only. Here is a case series of four cases of hypnic jerks found to be associated with the use of various SSRIs, Escitalopram, Sertraline, and Fluoxetine. Clonazepam was found to be very effective in reducing the hypnic jerks associated with SSRIs. In all the cases, the sleep-induced Electroencephalogram was normal.

INTRODUCTION

Hypnic jerk, also known as hypnagogic jerk or sleep start, is a type of myoclonic jerk that occurs during the onset of sleep and is experienced as a brief and sudden involuntary contraction of the body muscles. It is a common physiological event, experienced by 70% of people at least once in their lifetime, with no adverse neurological sequelae.[1] Although it occurs randomly in healthy individuals of all ages during the onset of nonrapid eye movement (N-REM) sleep (stage 1), repeated and intensifying jerks may disrupt sleep and be distressing. Often it is accompanied by a rapid heartbeat, rapid breathing, sweating, a peculiar sense of “falling into the void,” a vivid dream, or sometimes hallucinations.[2-4] Hypnic jerks can be precipitated by many stimuli, including anxiety, stress, sleep deprivation, stimulants like caffeine and nicotine, and strenuous physical activities.[4-6]

Escitalopram, Sertraline, and Fluoxetine are common selective serotonin reuptake inhibitors (SSRIs) that are regularly used to treat depressive disorder, anxiety disorder, and obsessive-compulsive disorder in both adult and adolescent patients.[7] Escitalopram-induced hypnic jerks were reported in recent literature[8] but were very few and not clearly differentiated from other similar conditions like restless leg syndrome, periodic limb movement disorder, and epileptic myoclonus by a proper clinical description and EEG. Removal of precipitating factors, if any, and low-dose Clonazepam were found to be very effective in reducing hypnic jerks.[1,8]

We are reporting here four cases of SSRI-induced hypnic jerks, clearly differentiated from other similar conditions by appropriate history and EEG findings and relieved by clonazepam. Written and informed consent was taken from all of our four patients.

Case 1

Mr. A.S., a 36-year-old married male, businessman by profession, from rural Bengal, visited a local medical college with a history of recent onset low mood, decreased interest in daily activities and business, decreased sleep, decreased appetite, hopelessness, and occasional suicidal ideation for the last 20 days. He had no previous history of a similar episode or other episodes indicating symptoms of mania or hypomania. He was not diabetic or hypertensive, and he had no history of convulsions. The physical examination did not find any significant abnormalities. During the mental status examination, he was found depressed, hopeless, and helpless with mild suicide intent and without any obvious delusion or hallucination. He was diagnosed as suffering from major depressive disorder according to International Classification of Diseases (ICD) 10 diagnostic criteria, and his score was 24 on the 17-item Ham-D scale, indicating severe depression. He was put on Tab. Escitalopram 10 mg, once daily, and the dose was increased to 15 mg after 1 week. He was reviewed after 2 weeks, and there was improvement in depressive symptoms with a decrease in Ham-D score to 16. But he complained of a new symptom that occurred 10 days after starting Escitalopram and appeared while going to sleep. After going to bed, within the first 10 to 15 minutes, he suddenly had a brisk jerking of his right leg, and it was so frightening that he woke up from bed. Later, he again fell asleep. On the next day, he experienced the same thing but in his left leg with jerky movements of the body and a sensation of falling from height. It became very frightening and disturbing for him. The next 2 days of sleep were uneventful, but he experienced it again last night. There was no history of unconsciousness, frothing at the mouth, or incontinence during those jerky movements. He had also no history of screaming, talking, moving his limbs during deep sleep, or having fearful dreams. He was suspected of having hypnic jerks. The seizure was ruled by a normal sleep-induced EEG, and he was given tab clonazepam at a dose of 0.5 mg at night before sleep and was reviewed again after 4 weeks. His depressive symptoms improved by 70%, and he did not feel any jerky movements of the body any further. The Naranjo[9] Adverse Drug Reaction Scale was applied with a score of 7, which indicated a probable adverse drug reaction.

Case 2

Mrs. P.L., a 40-year-old married lady, attended a private psychiatry clinic with a history of persistent and excessive worry about day-to-day events, excessive thinking, plans, and solutions to all possible worst outcomes of events, indecisiveness, and feelings of nervousness, trembling, and palpitation for the last 8 months. She was not diabetic or hypertensive, and she was euthyroid. Mental status examination revealed the presence of anxiety and excessive worry about most of the daily events. She was diagnosed as suffering from generalized anxiety disorder according to ICD-10 diagnostic criteria and her score on the Ham-A scale was 20—moderate anxiety. She was advised to take tab sertraline 25 mg at night for the initial 6 days, and then it was increased to 50 mg for the next 15 days. She was reviewed after 20 days, and with treatment, her anxiety symptoms improved by 50% on the Ham-A scale. She informed that she is having brief and sudden involuntary contractions of her body, sometimes of either or both legs and hands, occurring within the first 15 minutes of falling asleep. It started after increase in her dose, and she woke up suddenly for a moment with a jerking of her body. There was no history of loss of consciousness, frothing, fearful dreams, talking, walking, or jerking during the rest of her sleep. She was suspected of having hypnic jerks due to Sertraline and was given a tab of Clonazepam 0.5 mg along with Sertraline at night. She reported no such jerky movement later, and her sleep-induced EEG report was found normal. The Naranjo Adverse Drug Reaction Scale was applied with a score of 8, indicating a probable adverse drug reaction.

Case 3

Mrs. M., a 24-year-old unmarried lady, visited the psychiatry OPD of a medical college with complaints of recurrent, intrusive, and disturbing thoughts of getting contaminated by the COVID virus for the last 6 months. Although she can identify those thoughts as senseless, she cannot stop them from coming into her mind, and she is compelled to wash her hands and her belongings like mobile phones, pens, books, and utensils with sanitizer repeatedly. It is so distressing for her that she used to spend most of the time cleaning her objects and gradually avoided touching them to not get COVID infection. She had no other history suggestive of psychosis, generalised anxiety disorder, or depression. She was diagnosed as suffering from obsessive-compulsive disorder according to ICD-10 diagnostic criteria. She was given tab Fluoxetine 20 mg after lunch, which was gradually increased to 60 mg in the next 14 days. When she revisited after 20 days, her obsessive symptoms had improved by 25% on the Yale-Brown Obsessive-Compulsive scale (Y-BOCS). But she complained that she was having newly onset brisk jerks of her body along with her legs whenever she was falling to sleep. Jerks were brisk, nonrepetitive, and occurring most nights for the last 15 days. Sometimes there was a peculiar sensory feeling of falling into the void within 20 minutes of getting sleep and she woke up for a moment. There was no history of unconsciousness, tongue bite, frothing, or incontinence during those sudden jerky movements. She also did not have talking, walking, or movement of limbs during the rest of her sleep, and there was no daytime drowsiness. A fluoxetine-induced sleep start or hypnic jerk was suspected, and she was advised to take a tablet. Clonazepam, 0.5 mg after dinner for the next 15 days. Her hypnic jerks got better, and later Clomipramine was added with Fluoxetine for her obsessive symptoms. A computed tomography scan of the brain and sleep-induced EEG reports were advised and found normal. The Naranjo Adverse Drug Reaction Scale was applied with a score of 7, which indicated a probable adverse drug reaction.

Case 4

Mr. P.M., a 55-year-old married male patient, attended a local private psychiatry clinic with a history of a second episode of persistently depressed mood, decreased interest in his job, fatigue, decreased appetite, a feeling of hopelessness and helplessness, suicidal ideation, and decreased self-confidence for the last 2 months. He had a past history of the same episode 2 years ago after losing his job due to the COVID pandemic, which improved with treatment with Sertraline, but he discontinued treatment after 7 months and remained symptom-free for nearly 1 year. He had no past episodes of mania, hypomania, or psychosis. He was also suffering from diabetes mellitus and was being controlled with an oral hypoglycemic agent. Mental status examination revealed depressed mood, hopelessness, helplessness, and worthlessness with moderate suicidal ideation. He was diagnosed as suffering from recurrent depressive disorder, with the present episode being severe according to ICD-10 diagnostic criteria. His score on the 17-item Ham-D scale was 26, indicating severe depression. He was advised to take tab. Sertraline, 25 mg at bedtime, gradually increased to 75 mg in the next 15 days. His depressive symptoms improved with Sertraline, and his score on the Ham-D scale was reduced to 15. He complained of brief, sudden, involuntary jerky movements of his body, legs, and sometimes hands while falling asleep, which appeared fresh in the last 10 days after starting Sertraline. He can remember that he had similar abrupt, random, jerky movements of the body during the first 15 minutes of getting sleep in a previous episode of depression after starting antidepressant medication and that they continued infrequently until he stopped his medication. There was no history of unconsciousness, tongue bite, frothing, or incontinence during those jerks. The rest of his sleep was uneventful, and he had no history of daytime drowsiness. He was suspected to have hypnic jerks and was given tab. Clonazepam 0.5 mg at night along with sertraline. Surprisingly, his jerks during sleep vanished, and a later dose of sertraline was increased to 100 mg for relief of depressive symptoms. His sleep-induced EEG tracing was normal. The Naranjo Adverse Drug Reaction Scale was applied with a score of 9, which indicated a definite adverse drug reaction.

DISCUSSION

Hypnic jerks are mostly physiological, and according to the American Academy of Sleep Medicine, anxiety, stimulants like caffeine and nicotine, strenuous activities, stress, fatigue, and sleep deprivation may precipitate them.[5] There are various hypotheses proposed behind hypnic jerks, but none has been fully accepted.[5] Whereas one hypothesis postulates that a hypnic jerk is a form of reflex in response to normal bodily events during the first stages of sleep, another theory says that the body’s mistaken sense of relaxation, felt when falling asleep, results in sudden hypnic jerks.

SSRIs are well known to cause sleep disturbance, mostly REM sleep behavior disorder, but N-REM disorders like bruxism have also been reported.[10,11] Escitalopram-induced hypnic jerks, a N-REM sleep movement disorder, were reported by very few researchers,[8] which improved with Clonazepam. We also found hypnic jerks that started after starting various SSRI, like Escitalopram, Sertraline, and Fluoxetine, in depression and other anxiety disorders, which again also improved with Clonazepam in every case. In one of our cases, hypnic jerks were precipitated by the antidepressant Sertraline in a previous episode, which stopped after omitting Sertraline and reappeared in the current episode with a restart of Sertraline. We applied the Naranjo adverse drug reaction scale to all four of our cases, and three indicated probable and one indicated a definite adverse drug reaction. We found a clear association between hypnic jerks and the use of various SSRI medications.

Other physiological and medical conditions may mimic hypnic jerks, like restless leg syndrome, periodic limb movement disorder, and myoclonic epilepsy. Where restless leg syndrome is mostly caused by voluntary leg movements to uneasy sensation in legs during onset of sleep,[12,13] we found our cases to be involuntary, jerky, and brief contractions of the body and limbs during onset of sleep, favoring hypnic jerks. Periodic limb movement disorder is a N-REM sleep disorder characterized by recurrent episodes of frequent limb movements throughout the sleep.[13] Hypnic jerks are differentiated from it by the onset of movements in the first 15-20 minutes of sleep, stage 1 of N-REM sleep, as found in all of our cases. Myoclonic epilepsy and other epileptic convulsions are characterized by sudden, violent, irregular movements of the body caused by involuntary contraction of muscles. Generalized epileptic convulsion is frequently associated with loss of consciousness, tongue bite, frothing from the mouth, and urinary or fecal incontinence. In none of our cases did we find similar associated symptoms suggestive of epileptic convulsion, and in every case, normal sleep-induced EEG findings were mostly favorable to the diagnosis of hypnic jerks.

SSRI-induced hypnic jerks are rarely reported in the literature, and the only reported case was with Escitalopram. We have found hypnic jerks with the use of other SSRI like Sertraline and Fluoxetine along with Escitalopram; thus, it seems to be common with all SSRI medication. All psychiatrists must be aware of the hypnic jerks associated with SSRI medications, which can be readily relieved by Clonazepam.

Declaration of patient consent

The authors declare that they have obtained consent from patients. Patients have given their consent for their images and other clinical information to be reported in the journal. Patients understand that their names will not be published and due efforts will be made to conceal their identity but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.