A brief overview of sleep disorder diagnosis, part 1

Over 80 major sleep disorders exist. This number also keeps changing and differs widely depending on the source and classification system you are using. For a psychiatrist, there are about 3 major classification systems to keep track of (Table 1).

Table 1. Major classification systems

NameVersionAuthorsYear
DSMDiagnostic and Statistical Manual of Mental Disorders5American Psychiatric Association2013
ICDInternational Statistical Classification of Disease11World Health Organization2019*
ICSDInternational Classification of Sleep Disorders3American Academy of Sleep Medicine2014

*considered a preview, for implementation in 2022.

Sleep disorders encompass many fields, if not all, of medicine. Its diagnosis and management starts already at your primary care physician (or general practitioner) and extends into the fields of Neurology, Psychiatry, Respiratory Medicine, Cardiology, Ear Nose and Throat specialists and others. A brief overview of the roles and function of some of these care providers follows in Table 2.

Table 2. Various medical specialities involved in diagnosis and management of sleep disorders

General Practitioner Early detection, screening and detection of general medical conditions that may affect sleep and alertness (thyroid, kidney, brain, respiratory, adrenal, and other conditions such as vitamin deficiencies, obesity), choice of appropriate medication for general medical conditions (commonly used medication may cause insomnia, drowsiness or alter sleep in various ways, e.g. antihypertensives commonly cause insomnia), referral to an appropriate specialist, promotion of good sleep hygiene and the use of appropriate special investigations (blood tests, polysomnography/sleep study).
Respiratory MedicineLung disease such as Asthma, Chronic Obstructive Airway Disease (also known as emphysema or COPD), and other may severely alter the ability to fall asleep (breathlessness or treatment of the aforementioned disorders may cause severe insomnia) or stay asleep (altered ability to maintain the optimum blood oxygen saturation level ≥ 90%) may cause patients to wake up gasping for air, or simply insidiously alter normal sleep architecture (periods and duration of different phases of sleep during a normal night’s rest) and cause severely unrefreshing sleep.
CardiologyUnstable cardiac disease can lead to sleep-disordered breathing. Cardiac failure might also cause difficulty breathing, especially when lying down. This is called orthopnoea. People suffering from this condition may wake up short of breath that is relieved with a change in posture to the upright. Chronic sleep deprivation also increases the prevalence of cardiovascular disease.
Ear, Nose and ThroatThe upper airways are perhaps most implicated with sleep-related breathing disorders. Obstructive sleep apnoea (OSA) is amongst the most common sleep disorders and is becoming more relevant with increasing rates of obesity worldwide. Obesity is by no means the only cause of OSA. Other causes are often anatomical in origin, e.g size and shape of the tongue, large tonsils, dental/jawbone related, etc. Something as common as rhinitis or nasal septal defects may further worsen sleep apnoea or have their own effects on sleep architecture. In some cases, surgery might be indicated along with medical optimization of comorbid conditions, e.g. appropriate use of intranasal corticosteroids. In cases where surgery is not indicated (e.g. gold standard of treatment being medical management first, unstable medical condition, age, prior surgery have failed, patient preference, etc.) the use of CPAP (Continuous Positive Airway Pressure) devices may be indicated.
NeurologySome sleep disorders are best treated by a neurologist. These include sleep related movement disorders (periodic limb movement disorder, idiopathic restless leg syndrome), nocturnal epilepsy, neurological conditions affecting muscular activity (myasthenia gravis, motor neuron disease, etc), Parkinson’s Disease/PD (drugs used to treat commonly cause insomnia and somnolence, REM sleep behaviour disorder/RBD is commonly associated with PD and other neurodegenerative disorders), Narcolepsy and many more.
PsychiatryI cannot think of a single psychiatric disorder that is not linked in some way to the way we experience sleep. In my experience, the most common conditions linked to sleep disturbances are Depressive Disorders, Adjustment Disorders, Anxiety disorders, Bipolar Disorder, Substance use disorders, ADHD and Neurocognitive Disorders (Dementia and Delirium). Psychotropics can often either cause insomnia or daytime somnolence. These effects are exacerbated by drug interactions, dose, metabolism/pharmacogenomics (certain individuals will either rapidly or slowly metabolise certain drugs depending on liver enzyme expression). ‘Primary’ sleep disorders may also exist in the absence of other mental health conditions. This includes parasomnias (abnormal behaviour during sleep), insomnia disorder / primary insomnia, hypersomnolence disorder and many others.

Only peeking at the above lists might seem daunting to patient and clinician and might seem impossible to find the correct place to start looking for a diagnosis or treatment. I disagree, diagnosing a sleep disorder already starts at home. Always exclude contributing effects of poor sleep hygiene first, hence the plethora of previous posts purely about that topic. Get a detailed account of your sleeping habits. More data always makes the clinician’s job easier, this could include keeping a sleep diary (there are many apps available, or free online versions such as the one I made, but the humble piece of paper would do just fine). A bed partner’s or caregiver’s detailed account, or even better – video evidence of the suspected abnormal sleep behaviour will further aid the diagnosis. Thereafter you should visit your primary care physician to present your complaints. After a detailed history taking, thorough physical examination, and if needed requesting appropriate investigations your general practitioner may already know what the correct treatment should be or he/she may refer you to an appropriate specialist for further management. If you are already known with a condition that affects sleep, you should visit your treating specialist clinician with updated information and review of your condition.

More information will follow in future posts.

As always, wishing you good sleep.

Dr Schalk Wiehan Van Der Merwe

A well-built building starts with a strong foundation

You might have heard of sleep-hygiene. For those who haven’t, it’s not getting into bed after you’ve showered and into freshly washed linen to boot.

I always say it doesn’t matter whether I prescribe the Kim Kardashian or Rolls Royce of sleeping tablets, it won’t help much if you’re using it on a shaky foundation. Note, the author does not believe Kim = a Rolls. Furthermore, there is no such thing as a top-of-the-line sleeping tablet, only treatment (not necessarily medication) tailored to your specific needs.

What is this foundation I am talking about? Well, it’s basically a set of behaviours we teach ourselves over time that tells our body when to fall asleep. We are, after all, creatures of habit.

The challenging thing is that most of us want immediate results. Sleep hasn’t caught up with modern times. Most of us suffer from this desire for instant reward. If we want to know what the capital of Bulgaria is, we google it (it is Sofia); if we want to speak (read: chat) to someone, we instant message; if we are hungry, we click a few buttons and sushi arrives at our doorstep. By now you should understand what I am trying to convey here. Changing behaviours aimed at increasing your quality and quantity of sleep sometimes takes a bit more time to pay dividends, but oh boy does it pay dividends! Whatever changes you implement, try and be consistent by giving it a week or two before you dismiss its effects on your sleep. Going to bed at the same time isn’t so important as getting out of bed at the same time each day. If you have severe insomnia, go to bed when you are tired to help break the cycle and to improve your sleep efficiency (time spent in bed vs. time actually spent sleeping).

Some people simply spend too much time in bed! The bed is only for two things. Sleep and Sex. If you aren’t doing either of those things, it’s time to get out of bed. Most authors agree if you’re lying awake in bed for longer than 25 minutes you are basically teaching your brain that the bed isn’t a place for sleep. Tossing and turning is stressful and anxiety provoking. That is not a state that is conducive to good sleep. There are plenty of things you should rather be doing instead. Go to a dimly lit room and meditate, read a book or listen to relaxing music until you are tired enough to fall asleep. Avoid too much light (especially white/blue light) exposure within 2 hours of bedtime. Think about the effects that scrolling through an endless stream of social media posts on your phone around bedtime would do to your sleep! This type of light can suppress the effects of melatonin, the body’s natural sleep hormone.

Tomes could be written about the effects of caffeine, diet, alcohol, exercise (too much, at the wrong times, or too little of it) and light exposure. In time I’ll cover all of these topics. In the meanwhile, I encourage you to review my sleep hygiene handout (2 pages only!) at goodsleep.co.za

In summary:

  • Have a routine, get out of bed at the same time each morning (avoid sleeping in, even over weekends)
  • If you have insomnia, go to bed when you are tired
  • Don’t toss and turn (the bed is only for sleep and sex)
  • Limit caffeine intake and consume only before midday
  • Get early morning bright light exposure if possible
  • Exercise in the first part of the day, not close to bedtime
  • Avoid daytime naps (unless there is a safety concern)
  • Avoid smoking close to bedtime (nicotine put men on the moon!)
  • Don’t give up hope.
These aren’t just celebratory cigars, but nicotine to help stay awake! Nicotine is a potent nervous system stimulant.

Wishing you good sleep,

Dr Schalk Wiehan Van Der Merwe

The journey has been long, but it’s not over.

So you’ve found your way to a medical blog about sleep, probably at 3 am right? You’ve probably tried everything at this point, every old wives remedy, every over the counter tincture, oil and pill and you’re still not sleeping well.  I know the journey has been tough for many reading this, but I want to tell you it’s not over yet.

A mentor of mine once said,

There is always hope until the point there is no hope anymore.

I can only think of one situation where there is no hope anymore. The good news is, if you’re still reading this there is still hope.

I’ve been considering for days where to start with this blog. What tips to give first. What advice can I give that will help most people quickly? I think this urge stems from a culture of immediate gratification, quick fixes, and clickbait articles. I had to take a step back before I knew where to start. My first and most vital piece of advice I want to give is: Acceptance.


Acceptance is the only way out of hell.

Marsha Linehan

We’re not condoning this suffering you face, but accepting that you have this difficulty and that you need to do something about it. The second part of acceptance is, accepting that sleep disorders are often not fixed overnight and that it will take some work. This brings me to something another of my mentors once pivotally stated:

No great achievement can be had without sacrifice.

Sacrifice does not have to be in the biblical sense (this blog does not advocate animal sacrifice in order to sleep better!). It can simply be implementing change: whether it’s weight loss, cutting down drinking or quitting nicotine or finally breaking the silence and speaking to someone about your anxiety, depression or OCD, or realizing that excessive sleeping tablet use has never really helped you or have only really helped in the ultrashort-term. It’s time to talk to someone.


Stay tuned for more information about sleep. We’ll take this journey together, it is not over yet.

Dr Schalk Wiehan Van Der Merwe
Psychiatrist.

Hello, good night.

“To die, to sleep – to sleep, perchance to dream – ay, there’s the rub, for in this sleep of death what dreams may come…”

William Shakespeare, Hamlet

You may be familiar with the above quote, or more so with the same dread Hamlet faced. Hamlet, deeply affected by the murder of his father, suffered from severe melancholic depression and profound terminal insomnia. Today we understand that sleep disturbances can occur in the absence of mental illness, but also cause or be a consequence of mental or physical illness.