How is insomnia diagnosed?

How is insomnia diagnosed?

How is insomnia diagnosed?

When should you see a doctor for insomnia?

It’s fairly common to experience a night or two of disrupted sleep. When sleep disturbances begin to impact your normal daily function, it is time to consult a medical professional for treatment.

It is best to seek professional medical care before the effects of sleep problems escalate to a level where functioning becomes unsafe (e.g. symptoms cause an increased risk of motor vehicle accidents due to impaired capacity to drive safely and with sound judgement). 

Who to consult with when you’re suffering from insomnia

The first port of call can be a visit to a primary care physician (general practitioner) who can help to determine whether insomnia is in fact being experienced and help to identify why. A general practitioner can also diagnose and treat more transient episodes of insomnia, helping to resolve sleep disturbances reasonably quickly (often within a matter of weeks).

A general practitioner may refer a patient to a specialist in the case of chronic insomnia, and where there is evidence of comorbid medical conditions. Depending on the nature of coexisting condition, an appropriate specialist will be recommended – such as a psychologist or psychiatrist, rheumatologist, neurologist etc. who is better equipped to treat the underlying medical condition.

A sleep specialist may be useful if:

  • A patient has an identifiable history of disorders such as restless legs syndrome, periodic leg movement disorder or obstructive sleep apnoea.
  • Insomnia appears to have been triggered by psycho-physiological factors (i.e. apparent physical symptoms have arisen from emotional influences) over an extended period of time.
  • It is determined that a patient may require daily sedative treatment (with hypnotic medications) for at least 30 days or longer.

Sleep specialist centres often have trained psychologists specialising in the field of insomnia (and other sleep disorders) and can help to treat patients with skilled cognitive-behavioural treatment techniques. In-house staff can also better provide dedicated time for often-frequent follow-up consultations as well as assist with sleep education.

Diagnostic classification

A medical diagnosis of insomnia is generally conducted according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) or the International Classification of Sleep Disorders, Third Edition (ICSD-3).

The DSM-5 diagnostic classification is not necessarily used to make a distinction between the different forms of insomnia. It is, however, useful in helping to identify difficulties with initiating sleep, maintaining a state of sleep, frequent awakenings during the night or early mornings, and problems with being able to return to sleep. This generally defines a dissatisfaction with both quantity and quality of sleep.

ICSD-3 General Insomnia Diagnostic Criteria (all four areas apply for diagnosis)

One or more of the following are problematic:

  • Difficulty initiating sleep
  • Difficulty maintaining sleep
  • Early awakenings

Sleep difficulties occur even though a person does not have any notable challenges with circumstance or opportunity to achieve sleep.

Daytime impairments and problems in relation to sleep challenges or difficulties are experienced.

Sleep – wake challenges cannot be attributed or explained by any other sleep related difficulty or disorder.

ICSD-3 Requirement for Short-term Insomnia Diagnosis:

  • Acute insomnia symptoms must be present for under a 3-month period

ICSD-3 Diagnostic Criteria for Chronic Insomnia (16)

1. Criteria A:

At least one or more of the following is observed by a medical practitioner (and noted in a diagnostic report) or patient caregiver / parent:

  • Difficulties with falling asleep
  • Difficulties in maintaining sleep
  • Early awakenings (awaking earlier than required or preferred)
  • Resisting an appropriate bedtime schedule
  • Sleep difficulties without intervention attempts by a caregiver or parent

2. Criteria B:

At least one or more of the following effects of sleep difficulties are observed by a medical practitioner (and noted in a diagnostic report) or patient caregiver / parent:

  • Malaise
  • Fatigue / lethargy
  • Daytime sleepiness
  • Memory problems
  • Problems with paying attention or concentrating
  • Irritability
  • Mood disturbances
  • Aggression
  • Impulsive behaviours
  • Hyperactive behaviours
  • Lack of initiative or motivation
  • Challenges or impairments relating to academic, occupational, social or family life
  • Expression of concern over a lack of sleep or a general dissatisfaction regarding the quality of it.
  • Signs of being accident prone or the making of errors

3. Criteria C

Sleep challenges or difficulties cannot be attributed to an insufficient opportunity to achieve sleep (i.e. sleeplessness is not influenced by a disruption that is within the patient’s control – such as within the sleep environment).

4. Criteria D

Sleep challenges and difficulties, and resulting daytime problems occur at least 3 times per week.

5. Criteria E

Sleep challenges and difficulties have been occurring for at least 3 months.

6. Criteria F

Sleep challenges and difficulties do not fit the criteria of any other sleep disorder or sleeping complaint, such as short-sleep duration (there are no signs of daytime impairment even with fewer hours of night-time sleep), chronic sleep insufficiency (sleep restriction or insufficient opportunity to achieve sleep), delayed sleep-wake phase disorder (“night-owl”), advanced sleep-wake phase disorder (falling asleep during the early evening and awakening during early morning hours) etc.

*In the case of an ‘other’ diagnosis, general symptoms may be present but cannot be distinctly categorised as either a short-term or chronic condition.

Diagnosis and tests

1. Medical review and evaluation

A thorough medical evaluation is necessary in order to make the most accurate diagnosis and thus be able to implement the best means of treatment thereafter.

Essential evaluations a doctor will likely recommend involve:

  • A medical and psychiatric questionnaire / review: This is to determine any potential comorbid / coexisting health conditions (related to both medical and mental health).
  • A sleepiness evaluation: A common assessment which is used is the Epworth Sleepiness Scale which aims to differentiate sleepiness from tiredness or fatigue. The assessment requires the patient to rank their likelihood of falling asleep or dosing off during select activities which can be engaged in during the day. A score of the supplied ratings then determines a level of sleepiness. (17)
  • A sleep log (diary or study): This evaluation normally spans a one to two-week period and helps to determine sleep-wake patterns, as well as any notable variability relating to behaviour or sleep scheduling factors. -The keeping of a sleep log or analysis is important in the evaluation and diagnosis of insomnia as it can help to determine the nature and severity of a person’s condition.

Obtaining a comprehensive history is of the greatest importance during the medical evaluation, which will need to cover the following areas: 

Sleep history

The diagnosing doctor will carefully note a detailed sleep history of the patient. This will help to determine:

  • The type of sleep disturbance being experienced (i.e. problems with initiating sleep and / or difficulties in maintaining sleep).
  • The duration of sleep disturbances being experienced (i.e. insomnia that can be characterised as transient / acute or chronic).
  • The course of sleep disturbances being experienced (i.e. insomnia that is possibly recurrent or persistent).
  • Any factors which exacerbate or alleviate symptoms of insomnia.

The sleep history will also need to detail the timing of a sufferer’s insomnia experiences, and determine their typical sleep schedule, sleep habits (and various sleep hygiene factors). The sleep history will also assist a doctor to either identify or rule out any other potential sleep disorders which are associated with insomnia.

A doctor will use the evaluation to determine whether any associated insomnia triggering stimulants such as consumption of caffeinated beverages, or use of medications, illicit drugs or alcohol, as well as distractions like electronic devices and television are playing a role in the condition.

Some common questions which can be asked during such an evaluation include:

  • Do you have difficulty a) falling asleep, b) waking up in the middle of the night, c) wakening earlier in the morning than you’d like to?
  • How long have you been having difficulties with attaining quality sleep? (I.e. odd nights or just about every night? Has this been happening for days, weeks or months?)
  • Do you feel sleepy when you retire to bed at night?
  • Do you have a regular bedtime and wake-up time in the mornings?
  • Do you have difficulty keeping a regular bed time? Do you make an effort to wake up at the same time every day? Does this include weekend days and holidays?
  • Have you recently changed your sleep-wake schedule or routine?
  • Are there obvious distractions within your sleeping environment that influence your ability to sleep (i.e. an uncomfortable bed mattress or room temperature, or is the room exposed to excess light or noise)?
  • Have you noticed that you are able to achieve better sleep when you are away from home (e.g. at the residence of a friend or family member, or at a hotel) or even in a chair (i.e. not your own bed)?
  • Do you a) relax before bedtime or engage in work-related activities, b) read or watch television close to bedtime, c) keep a light or television on during the night?
  • If you have trouble falling asleep (or falling back to sleep once awoken during the night), what do you typically do (i.e. do you stay in bed, toss around, clock watch, or get up, read or watch television)?
  • Do you snore? Does this frequently awaken you? Do you wake up feeling out of breath (i.e. gasping)? How often does this happen?
  • Are you able to fall back to sleep easily if you awaken during the night?
  • Do you feel tired or fatigued throughout the course of the day? Or do you feel sleepy?
  • Do you try and take naps during the daytime? Are you able to?
  • Do you find that you tend to doze off during the day, or have trouble staying awake, especially while performing routine activities or tasks?
  • Do you have a regular exercise routine? At what time do you exercise?
  • Do you find yourself worrying or feeling increasingly anxious about being able to fall asleep, remain asleep or whether you will be able to get enough sleep at the end of the day? 

A doctor may also ask questions associated with possible symptoms that relate to other types of sleep disorders that they regard as relevant to the patient. These can include those related to obstructive sleep apnoea and restless legs syndrome (and / or periodic limb movement disorder).

If a person is truly struggling to sleep at night, he or she is likely to list a variety of daytime challenges and problems, such as:

  • Persistent fatigue and tiredness
  • Lethargy (lack of energy)
  • Difficulties with concentration
  • Focus and memory function
  • Consistent irritability and problems with overall academic
  • Social
  • Occupational performance

The sleepiness evaluation will be useful in determining whether a person is suffering from actual sleepiness during the daytime (which is not consistent with symptoms of insomnia, but may relate to another sleeping disorder type), or fatigue which is more aligned with insomnia.

Medical and psychiatric history

The diagnosing doctor will use this evaluation to determine whether there is a physical or mental health cause for the insomnia being experienced. He or she will try to identify whether there are any new or ongoing physical or mental health concerns (or conditions), as well as what kinds of medications or substances are being taken. He or she will also try and determine whether a recent (or current) stressful life event may be the root cause of sleep disturbances, such as a stressful change in the workplace, or home (like a divorce) or the loss of a loved one.

A doctor will touch on a patient’s leisure habits – work and exercise routines, long distance travel history (where relevant), and use of substances such as alcohol, medications, illicit drugs, tobacco and caffeine. Questions of this nature are useful in identifying potential clues related to insomnia symptoms, as any of these behaviours could be causing (triggering) or aggravating a person’s condition.

A thorough medical history will include a ‘review of systems’. To do this, a doctor will ask a patient about particular symptoms which relate to (where applicable) the skin, HEENT (head, eyes, ears, nose, and throat), neck, respiratory, cardiovascular, breast, gastrointestinal, genitourinary, musculoskeletal, neurological, psychiatric, endocrine and haematology systems in the body. The ‘review of systems’ refers to a reference sheet with a categorised list of symptoms which can be checked off as appropriate to a patient’s condition.

A doctor will also perform a psychological evaluation with the intention of screening for potential disorders, particularly anxiety and depression, which are closely linked with insomnia.  These are as follows:

Generalised anxiety disorder

Signs and criteria a medical doctor will look out for when conducting an evaluation include:

  • Excessive anxiety levels and worry occurring most days for at least 6 months (often relating to multiple issues or events).
  • Difficulties with getting bouts of worry under control.
  • Accompanying symptoms of restlessness or edginess, fatigue, issues with concentration and difficulty in focussing, muscle tension, sleep disturbances or trouble achieving sleep that is satisfying, and irritability.
  • Evidence of clinically significant distress in a person experiencing anxiety-related symptoms.
  • Distressing symptoms cannot be attributed to any other medical or mental health condition, or particular substance (medication or other) being taken.

A doctor will ask a handful of questions in order to quickly ascertain whether there is an existing problem with depression. He or she may ask questions such as:

  • Have you been feeling ‘down’ or depressed with a sense of hopelessness during the past month or so? Has this noticeably bothered you at all?
  • Have you noticed a developed disinterest in performing certain activities, or a change in a sense of satisfaction when participating in them?

A person who answers in the negative to both of these types of questions is not likely to be in a depressive state, and thus may not need a thorough evaluation in this regard. If answers indicate otherwise, a more comprehensive screening evaluation may be deemed necessary in order to make an appropriate diagnosis.

Family and social history

Along with a detailed personal medical and psychiatric evaluation, a doctor will wish to quickly determine if there is any risk of heritable conditions, like fatal familial insomnia in a person’s family line. Although rare, a doctor will check if a patient has any first-degree relatives with this condition which can be inherited.

A doctor will also try to determine if there are any other psychiatric disorders which may occur in the family line, placing a person at higher risk of developing these themselves.

Questions regarding social factors will also form part of the evaluation. For those experiencing more transient / short-term insomnia, a doctor will wish to determine the specific stress factors which may be contributing to the sleep disturbances.

If chronic insomnia is experienced, a doctor may question the sufferer regarding any potential past stressors, situations or events (as well as current stressors) which could have had an impact on the development of insomnia. A doctor will also try to determine whether a particular situational stress can be aligned with the onset of sleep disturbances (i.e. stress can be directly linked to when insomnia began).

A doctor will question a person regarding any smoking habits, or those relating to the consumption of alcohol and caffeine products. He/she will also ask whether any illicit drug use has been indulged in or not. It is important to be honest and disclose this information should it be relevant.

Medication use evaluation

A doctor will require a list of any medications (both prescription and over-the-counter) which have recently been taken or are being taken currently, including the use of supplements and herbal remedies. This line of questioning is important as many substances can contribute to the development of insomnia or cause interactions with other medications and substances that may cause sleep issues as side effects.

Medications that are known to cause insomnia in some users include:

  • Decongestants (like phenylephrine and pseudoephedrine)
  • Antidepressants (like fluoxetine and protriptyline)
  • Central nervous system stimulants (like dextroamphetamine and methylphenidate)
  • Respiratory medications (like albuterol and theophylline)
  • Hormone medications (like corticosteroids and those for the treatment of thyroid disorders)
  • Antiepileptic medications (like lamotrigine)
  • Anti-hypertensives (such as alpha blockers and beta blockers)

Evaluation considerations

In order for insomnia to be diagnosed, a doctor must be able to identify sleep disturbances that are accompanied by daytime fatigue and tiredness, irritability, concentration and focus issues, constant worry over sleep (and an anticipated lack thereof), a loss of overall motivation and obvious signs of daytime dysfunction.

A doctor will be looking to potentially identify (and or / diagnose or differentiate between) conditions other than insomnia, including depression, obstructive sleep apnoea, restless legs syndrome and periodic limb movement disorder and sleeplessness / circadian rhythm disorder.

2. Physical examination

Following the evaluation and personal and medical history review process, a doctor will conduct a physical examination. This is to check for any potential underlying medical conditions which may be influencing or causing sleep disturbances – particularly obstructive sleep apnoea, restless legs syndrome, periodic limb movement disorder or any neurological conditions. Such conditions can sometimes predispose a person to insomnia, and the presence of these may lead to a differential diagnosis.

If a doctor picks up on the possibility that a patient may be suffering from obstructive sleep apnoea during the consultation, he or she will carefully perform a head and neck examination. He/she will be looking for signs of a large neck size, enlarged tonsils and tongue, a low-lying soft palate, and signs of retrognathia (a small or retracted jaw) or micrognathia (an undersized jaw). Other signs to note also include a BMI (body mass index) of 30 or higher (a score typical of individuals who are obese).

He or she may recommend a Mallampati assessment during which a patient will be required to sit upright, open their mouth and stick out their tongue to the maximum. Based on what the doctor can see, a score will be given. Scores are determined as follows: (18) 

  • Class 0: All parts of the epiglottis should be visible – the epiglottis is the cartilage flap which is attached to the entrance of the larynx, pointing upwards behind the tongue. It normally remains open during breathing, so as to allow air into the larynx (voice box).
  • Class 1: The soft palate, fauces (opening at the back of the mouth), uvula (fleshy tissue which hangs over the tongue at the back of the mouth), and pillars (or palatine arches) will be visible.
  • Class 2: The soft palate, fauces and uvula will be visible.
  • Class 3: The soft palate and the base of the uvula will be visible.
  • Class 4: The soft palate will not be visible at all.

A score of 3 or 4 following this assessment will point a doctor in the direction of a potential obstructive sleep apnoea diagnosis.

If during the consultation, restless legs syndrome or any other particular neurological disorder is a concern, a doctor will perform a neurological examination. If a patient is consulting with a general practitioner, he or she will likely refer them to a neurologist to perform the specialist examination, which could take up to 90 minutes. The examination is performed in multiple (separate) steps focussing on areas of:

  • Higher functions (assessing gait, speech, mental status, memory function, orientation, intelligence and signs of psychological disturbances)
  • Cranial nerves (olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, vagus, glossopharyngeal, hypoglossal and spinal accessory nerves)
  • The sensory and motor systems
  • The motor system
  • Body reflexes (primitive, superficial, and deep tendon reflexes)
  • The cerebellum (which coordinates voluntary movements like balance, posture and speech)
  • Meninges
  • A systems survey (autonomic nervous system, neurovascular system, neurocutaneous system and skeletal system)

Should certain medical conditions be suspected or determined during this examination, the doctor may recommend specific tests which are best suited to diagnose a particular illness. Blood tests or various imaging tests, like X-rays, ultrasound scans, CT (computerised tomography) or MRI (magnetic resonance imaging) scans may be recommended for diagnostic purposes.

Patient undergoing a sleep study analysis at a sleep clinic

3. The sleep diary or sleep study

A doctor may recommend keeping a daily sleep diary for a period of between 1 and 2 weeks before any treatment therapy is initiated. (19) To be included in the diary are:

  • The time a person retires to bed
  • All sleep and wake times
  • Sleep durations and or / how long a person lays awake between dozing off
  • Daytime naps that are taken (i.e. when a nap is taken and for how long sleep was achieved)

In the diary, a patient will also need to keep a daily record of eating habits (food and beverages consumed, specifically caffeine or alcohol consumption), exercise and activity, as well as details relating to the taking of medications and / or supplements (i.e. what is taken, at what dosage, how often etc.).

The doctor will encourage a person to be as accurate in their recordings as possible so as to avoid any subjective assessment.

Findings from the diary will help a diagnosing doctor to determine specific irregularities in a patient’s sleep schedule. The diary will thus be used as part of the overall evaluation in order to both diagnose a form of insomnia and recommend tailored treatment for it. A doctor may also refer to the diary during the treatment process. Should a relapse occur following treatment, the diary will be used for reassessment.

A laboratory sleep study may be recommended but is not officially required for every case of insomnia. It can prove useful if a distinctive cause cannot be clearly identified. Recommended options for studying sleep patterns and evaluating irregularities include:

  • Actigraphy: An informal process (i.e. outside of a laboratory setting), this evaluation technique involves the wearing of a monitor or motion detector (usually on the wrist during the day and the night), recording movement and activity. The monitor or detector may be required to be worn over a period of a week, or up to two weeks, often while keeping a sleep diary / log. Estimate (or objective sleep measurements) data will be used to assess when a patient has been able to sleep. This technique has proved reasonably useful for the evaluation of circadian rhythm problems and disorders, particularly for the diagnosis of primary or paradoxical insomnia.
  • Polysomnography (PSG): A more formal sleep study is not routinely recommended for the evaluation of insomnia unless a doctor suspects underlying issues such as obstructive sleep apnoea or parasomnia sleep disorders.

If recommended, a patient will be required to stay overnight in a laboratory environment for evaluation. Monitors are attached the patient’s body in order to record brain activity, breathing (how much air is being inhaled and exhaled through the nose), heart rate, blood pressure, movement (including eye and chest movements) and various other (relevant) physiological functions (e.g. if a person snores).

Sleep is recorded in both a video and audio capacity as this helps to ascertain whether a person is achieving and proceeding through the numerous stages of sleep properly. Findings may be useful for further testing where applicable, which can involve blood or imaging tests. A doctor may also recommend this laboratory study if a person’s insomnia has not responded well to treatment attempts.

Should another sleep disorder (like narcolepsy or obstructive sleep apnoea) or even excessive daytime sleepiness be observed during a medical consultation, a multiple sleep latency test (MSLT) may be recommended. This test measures how quickly a person is able to fall asleep within an environment conducive to sleep during the daytime. Like polysomnography, it is not a routine testing process for insomnia.

Other potential testing evaluations

In rare instances, the following tests may be recommended where relevant:

1. Pulse oximetry or ABG (arterial blood gas) tests:

If there are signs that a person may have abnormally low levels of oxygen in the blood (hypoxemia), perhaps with a history of COPD (chronic obstructive pulmonary disease) and insomnia or other lung conditions, such tests may be recommended. Nocturnal hypoxemia can often develop prior to a condition being diagnosed, and includes signs such as wheezing, coughing, sweating, rapid breathing and shortness of breath. Such symptoms may co-exist with the development of insomnia.

Oximetry testing measures the oxygen levels in a patient’s bloodstream, as well as their heart rate. ABG testing involves extracting a sample of blood for the analysis of both oxygen and carbon dioxide in the bloodstream. Should results not indicate hypoxemia, overnight oximetry testing or an exercise desaturation study may be recommended. This is to determine whether or not a patient requires additional oxygen.

Nocturnal hypoxemia is normally consistent with daytime hypoxemia symptoms or those experienced following exercise. Oxygen therapy may be useful in alleviating the symptoms or severity of insomnia-related sleep disturbances.

2. Genetic testing:

In instances where a patient has at least 1 first-degree relative with insomnia, and especially if their condition progressed rapidly and they were struggling to overcome it at the time of their death, a doctor may suggest genetic testing for a rare condition known as fatal familial insomnia (FFI).

Testing involves the sequencing of the PRNP gene, which functions as the predominant encoding system for the major prion protein PrP (also referred to as CD230). This gene occurs in numerous bodily tissues, but is most prevalent in the nervous system. (20) 

Along with genetic testing, a doctor will also recommend PET (positron-emission tomography) imaging of the brain to assess for signs of hypometabolism (a low metabolic rate), by examining the thalamus and cingulate cortex regions. Together, the findings may be useful for diagnosing FFI.


16. European Sleep Research Society. 2014. Assessment of sleep disorders and diagnostic procedures:  [Accessed 04.08.2018] 

17. Centers for Disease Control and Prevention. 1990 - 1997. Epworth Sleepiness Scale: [Accessed 04.08.2018]

18. US National Library of Medicine - National Institutes of Health. December 2010. Mallampati Class Is Not Useful in the Clinical Assessment of Sleep Clinic Patients: [Accessed 04.08.2018]

19. HealthLink BC. 10 October 2017. Insomnia: [Accessed 04.08.2018]

20. National Center for Advancing Translational Sciences. January 2018. Fatal Familial Insomnia: [Accessed 04.08.2018]

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