Insomnia is characterized by a dissatisfaction with the duration and quality of sleep caused by difficulty falling asleep at night (sleep-onset insomnia), frequent or prolonged awakenings at night (maintenance insomnia) or early awakenings in the morning without being able to go back to sleep (terminal insomnia).
It is one of the most common sleep disorders. It is estimated that approximately 25% of the Canadian population experiences symptoms of insomnia. It can affect anyone, even children, but is more common in women, the underprivileged and those in poor health.
Insomnia can be related to a stressful event (e.g., work problem, bereavement, divorce, etc.). This is called acute insomnia, a condition that could last several weeks. It usually resolves itself when the triggering factor disappears.
Insomnia is often caused by bad sleep habits, such as drinking coffee or smoking cigarettes in the hours before bedtime, excessive alcohol consumption, intense activity late at night, an irregular schedule or a disruptive environment (e.g., noise, light, temperature, etc.).
It can accompany physical problems, such as heart and lung disease, musculoskeletal disorders and chronic pain, or psychological problems, such as depression and anxiety. It can also be associated with another sleep disorder, including obstructive sleep apnea, which is very often diagnosed in people who complain of insomnia or an inability to have a restful sleep.
In addition to having difficulty falling asleep and waking up during the night or early morning, people suffering from insomnia do not feel rested the next day. They may also experience various symptoms during the day, such as irritability, excessive fatigue (physical and mental), drowsiness and problems concentrating. In the long term, lack of sleep can disrupt daily activities, degrade quality of life, worsen the symptoms of other illnesses and cause accidents.
If symptoms of insomnia last only a few days, adopting better sleep hygiene can be beneficial. But if the difficulty in sleeping occurs at least three nights a week for more than three months, the insomnia is considered chronic and requires a consultation.
A health care professional will usually diagnose insomnia based on a patient’s complaints. To correctly identify the problem, it may be useful to keep a sleep diary for two or three weeks and record when and under what conditions the insomnia occurs, the severity of the episodes and their impact on daily life.
Chronic insomnia requires treatment adapted to each situation. The first step is to look for the cause and address it. Often, insomnia that has been present for several months also requires a reorganization of lifestyle habits to promote sleep. Sleep hygiene support can be helpful.
Cognitive-behavioural therapy for insomnia (CBT-I): This is the first treatment recommended for chronic insomnia. This type of psychotherapy uses different methods to restore the sleep-wake cycle and change inappropriate thoughts and behaviour. For example, when a person is unable to sleep and worries about the consequences of a sleepless night the following day, he or she may enter a vicious circle that CBT-I aims to short-circuit. A meta-analysis of 20 studies evaluating its effectiveness showed a significant improvement in sleep that lasted over time, with no harmful consequences for the participants (video available in french only). 
Medication: If insomnia persists, medication can be used. However, according to Charles Morin, a professor at Université Laval and a world authority on insomnia, medication does not eliminate the cause of insomnia and should be considered as an occasional lifeline. 
Sleeping pills, such as benzodiazepines and benzodiazepine-like hypnotics can be prescribed to help the patient recover somewhat, but for a short period of time (no more than three weeks), as they are addictive and lose their effectiveness after a few weeks.
Antihistamine hypnotics include most over-the-counter medications. They are not sleeping pills, but rather medications that cause drowsiness which are generally used to treat allergies. However, their effectiveness in treating insomnia has not been clearly demonstrated  and their side effects are similar to those of sleeping pills.
Melatonin is a hormone secreted by the brain which helps maintain the sleep-wake cycle. It is also available in synthetic form in over than a hundred products approved as natural health products in Canada. Although it promotes sleep and may be beneficial for some sleep disorders, its effectiveness in treating insomnia is believed to be limited. 
Chaput, Jean-Philippe, Jessica Yau, Deepa P. Rao and Charles M. Morin. “Prevalence of insomnia for Canadians aged 6 to 79,” Statistics Canada, Catalogue no. 82-003-X, Health Reports, Vol. 29, no. 12, p. 17-22, December 2018, https://www150.statcan.gc.ca/n1/pub/82-003-x/2018012/article/00002-eng.htm
Trauer, J.M., M.Y. Qian, J.S. Doyle, S.M. Rajaratnam and D. Cunnington. “Cognitive Behavioral Therapy for Chronic Insomnia: A Systematic Review and Meta-analysis,” Annals of internal medicine, 163(3), 191-204, 2015.
Proulx, Marie-Hélène. “À la recherche du sommeil perdu,” L’actualité, November 4, 2020, https://lactualite.com/societe/a-la-recherche-du-sommeil-perdu/
Culpepper Larry and Mark A. Wingertzahn. “Over-the-Counter Agents for the Treatment of Occasional Disturbed Sleep or Transient Insomnia: A Systematic Review of Efficacy and Safety,” The Primary Care Companion for CNS Disorders, Vol. 17, no. 6, Dec. 15, 2015, DOI: 10.4088/PCC.15r01798
Costello, Rebecca, Cynthia Lentino, Courtney Boyd, Meghan O'Connell, Cindy Crawford, Meredith Sprenel and Patricia Deuster. “The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature,” Nutrition Journal, Vol. 13, no. 1, p. 106, 2014. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4273450/