Paradoxical Insomnia: A Case Report

Abstract

A diagnosis of paradoxical insomnia is made in patients presenting with the complaint of insomnia despite normal polysomnographic findings. These patients argue that they never sleep or have little sleep only for a few hours. Pharmacological and non-pharmacological treatment options are available for the treatment of paradoxical insomnia. Although its prevalence can be as high as 50% in the clinical samples and studies, clinicians may not remember to include paradoxical insomnia in the differential diagnosis. In this article, we present a patient, who was diagnosed with paradoxical insomnia for the first time in our polysomnography laboratory. The patient had accompanying sleep apnea and responded to the treatment with olanzapine and psychoeducation, comprising polysomnographic video recordings and instructions of sleep hygiene. Because this is the first case presentation from our country, characterized by the abovementioned clinical features; we think that this article may increase clinician awareness and contribute to the information in the literature.

INTRODUCTION

Insomnia is one of the most common medical complaints (1). Sleep disorders are generally associated with physical illnesses, mental illnesses, and neurological disorders (2). It may also be associated with acute stress, drug or substance use, poor sleep habits, and changes in the sleep environment. Insomnia is defined as short-term and chronic depending on its duration (3). Paradoxical insomnia (PI) is used for patients with complaints of insomnia despite normal polysomnography findings. The terms “false insomnia” and “non-objective insomnia” were also used to describe this condition. Patients claim that they either do not sleep at all or sleep only for a few hours. These people do not show obvious psychopathology or malingering characteristics. They increase environmental awareness and mental activity while trying to sleep (4). The etiology of PI is not fully understood; it has been associated with personality traits, but its cause has not been established (5). Insomnia has high comorbidity with obstructive sleep apnea (OSA) (6). Assuming that insomnia is also commonly associated with sleep state misperception, patients with OSA are at risk for PI comorbidity. It is discussed under the name of “Sleep State Misperception” in the International Classification of Sleep Disorders (ICSD) 1 (7). In 2005, the term Sleep State Misperception was removed and named PI in ICSD 2, and it was included as a subtype of chronic insomnia (8). In the ICSD 3 classification, Chronic Insomnia subtypes (psychophysiological insomnia, idiopathic insomnia, insufficient sleep hygiene, and PI were removed because they could not be reliably distinguished in clinical practice (3). In this case report, we present a case with the complaint of insomnia, diagnosed with PI for the first time in our sleep laboratory and with OSA coexistence. Although its prevalence in clinical samples and studies can reach up to 50%, PI may not come to the mind of clinicians. Since PI treatment is different from other insomnia treatments, differential diagnosis is important. As far as we know, we think that this article can increase the awareness of clinicians and contribute to the literature since it is the first case reported in our country.

CASE

FU is 53 years old, married, a housewife, primary school graduate, lives in Kars with her husband and three children, applied to our outpatient clinic with the complaint of insomnia. She had her complaint for approximately 7 months and stated that she could not fall asleep, was constantly awake, and felt tired during the day. The patient did not have a history of smoking, alcohol, caffeine, substance use, or medical illness. Before the patient presented to us, amitriptyline 10 mg/day was used for one month, and amitriptyline was discontinued and Trazodone was initiated at 50 mg/day when the complaints continued, but the use of the drug was discontinued by the patient herself when the complaint continued. The patient, who did not apply to the hospital for about 5 months, presented to our outpatient clinic with the complaint of not being able to sleep at all, due to problems in her daily life. Laboratory and imaging tests were requested from the patient, who was seen in the outpatient clinic, to exclude possible organic etiology. In the neurological examination of the patient, who did not have a chronic disease, no pathology was found in routine biochemistry, blood count, hormone examinations, and brain magnetic resonance imaging. The patient was admitted to the sleep laboratory for polysomnographic evaluation. In polysomnography, 410.4 minutes of recording was made during the night, and the patient slept 215.5 minutes of this period. Sleep latency was 21.5 minutes, and sleep efficiency was 52.5%. The total abnormal respiratory event index was found to be 16.2/h and positional. It dropped to 8 after the change of position. Mean awake oxygen saturation was found to be 90.5%, and it was observed to decrease to 82% during abnormal respiratory events. When the patient’s history, mental state examination, polysomnography and other examinations were evaluated together, the diagnosis of PI and OSA was established for the patient.

DISCUSSION

Patients with PI typically complain of little or no sleep. These complaints are neither confirmed by the patient’s relatives nor by the sleep laboratory findings. Besides, since insomnia may be a symptom of another mental or physical illness, detailed examinations and laboratory tests are required when establishing a diagnosis of PI. No pathology was found in the medical examinations performed for our patient, who stated that she could not sleep at all. In the psychiatric examination and the history taken from the patient, comorbid medical and mental illness, substance and drug use were not found. In a study conducted in 2003, the prevalence of subjective insomnia/sleep state misperception was shown to be between 9.2% and 50% in clinical and research samples (9). Our sleep unit was established in 2008, and when 2,500 patients hospitalized in the sleep unit so far were screened, it was seen that no patients received this diagnosis. The reason why it is seen less may be that it is less known by doctors and, consequently, it is not considered as a diagnosis. Also, the exclusion of chronic insomnia subtitles in ICSD 3 may be one of the reasons why differential diagnosis is not made.

Harvey and Tang suggested increased cortical arousal, abnormal neuronal circuitry, and frequent night awakenings as etiological factors for paradoxical insomnia (10). Additionally, in a study evaluating the EEG frequency spectra, increased arousal during sleep was observed in PI patients (11). However, the difficulty in maintaining sleep in patients diagnosed with OSA can also be explained by the stimulation that occurs during sleep (12). Frequent arousal caused by increased respiratory events in patients with OSA can mimic the repetitive arousal that occurs in PI, thus causing the patient to confuse sleep and wakefulness. This situation may explain the association of OUA and PI. However, our patient did not receive any treatment for OSA except for a change in position.

There are pharmacological and non-pharmacological treatment approaches in PI treatment. Short-term use of benzodiazepines can improve sleep perception (13). Besides, olanzapine and risperidone have been shown to be effective in treatment while olanzapine has a higher effect (14). Psychoeducation and sleep hygiene, in which polysomnographic data were compared with the patient’s data with the help of a video describing polysomnography as a non-pharmacological treatment, were found to be beneficial (15). Our patient was started on olanzapine 5 mg/day. In addition, psychoeducation-based interviews were made including polysomnography video recording and sleep hygiene once a week. After 2 months, our patient started to express that she slept. Thereafter, interviews were made with the patient once a month. At the end of the 6th month, olanzapine treatment was discontinued, and the patient did not have any complaints in the next two-month follow-up. As seen in our case example, PI has a unique treatment strategy, and if left untreated, the patient becomes distressed and anxious due to insufficient sleep perception, which can eventually lead to objective sleep disturbance. Since paradoxical insomnia has high comorbidity with other medical and psychiatric disorders, and PI is one of the most common insomnia subtypes, a better understanding of paradoxical insomnia is essential. Nonetheless, there is little research addressing this disorder. We think our case can be a good example that highlights the importance of recognizing and investigating paradoxical insomnia.