Sleep disturbances often result from underlying mental disorders and not infrequently prompt the individual to seek treatment. The relation between sleep disorders and mood disorders has many theoretical implications as well. For instance, neurochemical theories regarding the etiology of depression have been complemented by theories regarding sleep regulation and the etiology of sleep disturbance in patients with depression. Specifically, an augmentation of cholinergic relative to monoaminergic neurotransmission has been hypothesized to underlie both the mood and the sleep disturbances of depression. In part because of these theoretical ties, a large body of research has accumulated regarding electroencephalographic sleep findings in patients with psychiatric disorders (Nofzinger et al. 1994).

Table 89-3 summarizes this literature, as well as the major treatments for sleep disorders associated with specific psychiatric conditions.

In general, the treatment of a sleep disorder related to another mental disorder should be targeted at the mental disorder; treatment of the underlying psychiatric condition is expected to improve sleep symptoms. Thus, a patient who presents with insomnia and depressive symptoms should show improvement in both mood and sleep with adequate treatment, whether psychotherapeutic or pharmacological. When the sleep complaint is out of proportion to the psychiatric diagnosis, other primary sleep disorders should always be considered. For instance, sleep apnea could be considered in a depressed, overweight, hypertensive man who does not respond adequately to antidepressant pharmacotherapy alone. Patients with PLM may actually experience an exacerbation of their condition with antidepressant medication. Finally, some patients have continued sleep symptoms despite adequate resolution of their psychiatric syndrome. In such cases, a diagnosis of primary insomnia or hypersomnia must be considered and appropriate treatment provided.

The treatment of specific psychiatric disorders is covered in detail elsewhere in this volume. In this section, we briefly review those aspects of treatment with particular relevance to sleep complaints.

307.42 Insomnia Related to Another Mental Disorder 307.44 Hypersomnia Related to Another Mental Disorder

Diagnostic Features

The essential feature of Insomnia Related to Another Mental Disorder and Hypersomnia Related to Another Mental Disorder is the presence of either insomnia or hypersomnia that is judged to be related temporally and causally to another mental disorder. Insomnia or Hypersomnia that is the direct physiological consequence of a substance is not included here. Such presentations would be diagnosed as Substance-Induced Sleep Disorder. Insomnia Related to Another Mental Disorder is characterized by a complaint of difficulty falling asleep, frequent awakenings during the night, or a marked feeling of nonrestorative sleep that has lasted for at least 1 month and is associated with daytime fatigue or impaired daytime functioning (Criterion A). Hypersomnia Related to Another Mental Disorder is characterized by a complaint of either prolonged nighttime sleep or repeated daytime sleep episodes for at least 1 month (Criterion A). In both Insomnia and Hypersomnia Related to Another Mental Disorder, the sleep symptoms cause significant distress or impairment in social, occupational, or other important areas of functioning (Criterion B). The insomnia or hypersomnia is not better accounted for by another Sleep Disorder (e.g., Narcolepsy, Breathing-Related Sleep Disorder, or a Parasomnia) and hypersomnia is not better accounted for by an inadequate amount of sleep (Criterion D). The sleep disturbance must not be due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition (Criterion E).

Sleep disturbances are common features of other mental disorders. An additional diagnosis of Insomnia or Hypersomnia Related to Another Mental Disorder is made only when the sleep disturbance is a predominant complaint and is sufficiently severe to warrant independent clinical attention (Criterion C). Individuals with this type of insomnia or hypersomnia usually focus on their sleep disturbance to the exclusion of the symptoms characteristic of the related mental disorder, whose presence may become apparent only after specific and persistent questioning. Not infrequently, they attribute their symptoms of mental disorder to the fact that they have slept poorly.

Many mental disorders may at times involve insomnia or hypersomnia as the predominant problem. Individuals in a Major Depressive Episode or who have Dysthymic Disorder often complain of difficulty falling asleep or staying asleep or early morning awakening with inability to return to sleep. Hypersomnia Related to Mood Disorder is more often associated with Bipolar Mood Disorder, Most Recent Episode Depressed, or a Major Depressive Episode, With Atypical Features. Individuals with Generalized Anxiety Disorder often report difficulty falling asleep and may awaken with anxious ruminations in the middle of the night. Some individuals with Panic Disorder have nocturnal Panic Attacks that can lead to insomnia. Significant insomnia is often seen during exacerbations of Schizophrenia and other Psychotic Disorders but is rarely the predominant complaint. Other mental disorders that may be related to insomnia include Adjustment Disorders, Somatoform Disorders, and Personality Disorders.

Recording Procedures

The name of the diagnosis begins with the type of sleep disturbance (i.e., insomnia or hypersomnia) followed by the name of the specific Axis I or Axis II disorder that it is related to (e.g., 307.42 Insomnia Related to Major Depressive Disorder) on Axis I. The specific related mental disorder should also be coded on Axis I or Axis II as appropriate.

Associated Features and Disorders

Associated descriptive features and mental disorders. Because, by definition, the criteria are met for the related mental disorder, the associated features of Insomnia or Hypersomnia Related to Another Mental Disorder include the characteristic and associated features of the related mental disorder.

Individuals with Insomnia Related to Another Mental Disorder may demonstrate the same type of conditioned arousal and negative conditioning that individuals with Primary Insomnia demonstrate. For instance, they will note increased anxiety as bedtime approaches, improved sleep when taken out of the usual sleep environment, and a tendency to spend too much time in bed. They may also have a history of multiple or inappropriate medication treatments for their insomnia complaints. Individuals with Hypersomnia Related to Another Mental Disorder will frequently emphasize symptoms of fatigue, “leaden paralysis,” or complete lack of energy. On careful questioning, these individuals may be more distressed by such fatigue-related symptoms than by true sleepiness. They may also have a history of inappropriate use of stimulant medications, including caffeine.

Associated laboratory findings. Characteristic (but not diagnostic) polysomnographic findings in Major Depressive Episode include 1) sleep continuity disturbance, such as prolonged sleep latency, increased intermittent wakefulness, and early morning awakening; 2) reduced non-rapid eye movement (NREM) stages 3 and 4 sleep (slow-wave sleep), with a shift in slow-wave activity away from the first NREM period; 3) decreased rapid eye movement (REM) latency (i.e., shorter duration of the first NREM period); 4) increased REM density (i.e., the number of actual eye movements during REM); and 5) increased duration of REM sleep early in the night. Sleep abnormalities may be evident in 40%-60% of outpatients and in up to 90% of inpatients with a Major Depressive Episode. Evidence suggests that most of these abnormalities persist after clinical remission and may precede the onset of the initial Major Depressive Episode.

Polysomnographic findings in Manic Episodes are similar to those found in Major Depressive Episodes. In Schizophrenia, REM sleep is diminished early in the course of an acute exacerbation, with a gradual return toward normal values as clinical status improves. REM latency may be reduced. Total sleep time is often severely diminished in Schizophrenia, and slow-wave sleep is typically reduced during exacerbations. Individuals with Panic Disorder may have paroxysmal awakenings on entering stages 3 and 4 NREM sleep; these awakenings are accompanied by tachycardia, increased respiratory rate, and cognitive and emotional symptoms with Panic Attacks. Most other mental disorders produce nonspecific patterns of sleep disturbance (e.g., prolonged sleep latency or frequent awakenings).

Laboratory testing of daytime sleepiness by the Multiple Sleep Latency Test in individuals with Hypersomnia Related to Another Mental Disorder often shows normal or only mild levels of physiological sleepiness compared with individuals with Primary Hypersomnia or Narcolepsy.

Associated physical examination findings and general medical conditions. Individuals with Insomnia or Hypersomnia Related to Another Mental Disorder may appear tired, fatigued, or haggard during routine examination. The general medical conditions associated with these Sleep Disorders are the same as those associated with the underlying mental disorder.

Specific Culture, Age, and Gender Features

In some cultures, sleep complaints may be viewed as relatively less stigmatizing than mental disorders. Therefore, individuals from some cultural backgrounds may be more likely to present with complaints of insomnia or hypersomnia rather than with other symptoms (e.g., depression, anxiety).

Children and adolescents with Major Depressive Disorder generally present with less subjective sleep disturbance and fewer polysomnographic changes than do older adults. In general, hypersomnia is a more common feature of Depressive Disorders in adolescents and young adults and insomnia is more common in older adults.

Sleep Disorders Related to Another Mental Disorder are more prevalent in females than in males. This difference probably relates to the increased prevalence of Mood and Anxiety Disorders in women rather than to any particular difference in susceptibility to sleep problems.

Prevalence

Sleep problems are extremely common in all types of mental disorders, but there are no accurate estimates of the percentage of individuals who present primarily because of sleep disruption. Insomnia Related to Another Mental Disorder is the most frequent diagnosis (35%-50%) among individuals presenting to sleep disorders centers for evaluation of chronic insomnia. Hypersomnia Related to Another Mental Disorder is a much less frequent diagnosis (fewer than 5%) among individuals evaluated for hypersomnia at sleep disorders centers.

Course

The course of Sleep Disorders Related to Another Mental Disorder generally follows the course of the underlying mental disorder itself. The sleep disturbance may be one of the earliest symptoms to appear in individuals who subsequently develop an associated mental disorder. Symptoms of insomnia or hypersomnia often fluctuate considerably over time. For many individuals with depression, particularly those treated with medications, sleep disturbance may improve rapidly, often more quickly than other symptoms of the underlying mental disorder. On the other hand, other individuals have persistent or intermittent insomnia even after the other symptoms of their Major Depressive Disorder remit. Individuals with Bipolar Disorder often have distinctive sleep-related symptoms depending on the nature of the current episode. During Manic Episodes, individuals experience hyposomnia, although they rarely complain about their inability to sleep. On the other hand, such individuals may have marked distress about hypersomnia during Major Depressive Episodes. Individuals with Psychotic Disorders most often have a notable worsening in sleep early during the course of an acute exacerbation, but then report improvement as psychotic symptoms abate.

Differential Diagnosis

Insomnia or Hypersomnia Related to Another Mental Disorder should not be diagnosed in every individual with a mental disorder who also has sleep-related symptoms. A diagnosis of Insomnia or Hypersomnia Related to Another Mental Disorder should be made only when sleep symptoms are severe and are an independent focus of clinical attention. No independent sleep disorder diagnosis is warranted for most individuals with Major Depressive Disorder who report difficulties falling or staying asleep in the middle of the night. However, if the individual primarily complains of sleep disturbance or if the insomnia is out of proportion to other symptoms, then an additional diagnosis of Insomnia Related to Another Mental Disorder may be warranted.

Distinguishing Primary Insomnia or Primary Hypersomnia from Insomnia or Hypersomnia Related to Another Mental Disorder can be especially difficult in individuals who present with both clinically significant sleep disturbance and other symptoms of a mental disorder. The diagnosis of Insomnia or Hypersomnia Related to Another Mental Disorder is based on three judgments. First, the insomnia or hypersomnia must be judged to be attributable to the mental disorder (e.g., the insomnia or hypersomnia occurs exclusively during the mental disorder). Second, the insomnia or hypersomnia must be the predominant complaint and must be sufficiently severe to warrant independent clinical attention. Third, the symptom presentation should meet the full criteria for another mental disorder. A diagnosis of Primary Insomnia or Primary Hypersomnia is appropriate when (as is often the case) the insomnia or hypersomnia is accompanied by symptoms (e.g., anxiety, depressed mood) that do not meet criteria for a specific mental disorder. A diagnosis of Primary Insomnia is also appropriate for individuals with chronic insomnia who later develop a Mood or Anxiety Disorder. If symptoms of insomnia or hypersomnia persist long after the other symptoms of the related mental disorder have remitted completely, the diagnosis would be changed from Insomnia or Hypersomnia Related to Another Mental Disorder to Primary Insomnia or Primary Hypersomnia.

Insomnia or Hypersomnia Related to Another Mental Disorder is not diagnosed if the presentation is better accounted for by another Sleep Disorder (e.g., Narcolepsy, Breathing-Related Sleep Disorder, or a Parasomnia).

Insomnia or Hypersomnia Related to Another Mental Disorder must be distinguished from a Sleep Disorder Due to a General Medical Condition. The diagnosis is Sleep Disorder Due to a General Medical Condition when the sleep disturbance is judged to be a direct physiological consequence of a specific general medical condition (e.g., pheochromocytoma, hyperthyroidism). This determination is based on history, laboratory findings, and physical examination. A Substance-Induced Sleep Disorder is distinguished from Insomnia or Hypersomnia Related to Another Mental Disorder by the fact that a substance (i.e., a drug of abuse, a medication) is judged to be etiologically related to the sleep disturbance. For example, insomnia that occurs only in the context of heavy coffee consumption would be diagnosed as Caffeine-Induced Sleep Disorder, Insomnia Type.

Sleep Disorders Related to Another Mental Disorder must be differentiated from normal sleep patterns, as well as from other Sleep Disorders. Although complaints of occasional insomnia or hypersomnia are common in the general population, they are not usually accompanied by the other signs and symptoms of a mental disorder. Transient sleep disturbances are common reactions to stressful life events and generally do not warrant a diagnosis. A separate diagnosis of Insomnia or Hypersomnia Related to Adjustment Disorder should be considered only when the sleep disturbance is particularly severe and prolonged.

Relationship to the International Classification of Sleep Disorders

The International Classification of Sleep Disorders (ICSD) includes analogous diagnoses for Sleep Disorders Related to Another Mental Disorder and specifically lists Psychoses, Mood Disorders, Anxiety Disorders, Panic Disorder, and Alcoholism.

Diagnostic criteria for 307.42 Insomnia Related to . . . [Indicate the Axis I or Axis II disorder]

A. The predominant complaint is difficulty initiating or maintaining sleep, or nonrestorative sleep, for at least 1 month that is associated with daytime fatigue or impaired daytime functioning.
B. The sleep disturbance (or daytime sequelae) causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
C. The insomnia is judged to be related to another Axis I or Axis II disorder (e.g., Major Depressive Disorder, Generalized Anxiety Disorder, Adjustment Disorder With Anxiety) but is sufficiently severe to warrant independent clinical attention.
D. The disturbance is not better accounted for by another Sleep Disorder (e.g., Narcolepsy, Breathing-Related Sleep Disorder, a Parasomnia).
E. The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.

Diagnostic criteria for 307.44 Hypersomnia Related to . . . [Indicate the Axis I or Axis II disorder]

A. The predominant complaint is excessive sleepiness for at least 1 month as evidenced by either prolonged sleep episodes or daytime sleep episodes that occur almost daily.
B. The excessive sleepiness causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
C. The hypersomnia is judged to be related to another Axis I or Axis II disorder (e.g., Major Depressive Disorder, Dysthymic Disorder) but is sufficiently severe to warrant independent clinical attention.
D. The disturbance is not better accounted for by another Sleep Disorder (e.g., Narcolepsy, Breathing-Related Sleep Disorder, a Parasomnia) or by an inadequate amount of sleep.
E. The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.