Sleeplessness, also known as insomnia, is one of the most common sleep complaints worldwide, characterized by persistent difficulty falling asleep, staying asleep, or waking up earlier than desired, despite having adequate opportunity and circumstances for sleep. Sleeplessness results in insufficient or non-restorative sleep and is associated with significant daytime impairment. Sleeplessness can be acute or chronic. Acute sleeplessness typically lasts for a few days to a few weeks and is often triggered by a specific stressor such as a difficult life event, illness, or travel. Chronic sleeplessness occurs at least three nights per week for three months or more and may persist for years if untreated. The causes of sleeplessness are multifaceted. Psychological factors — particularly stress, anxiety, and depression — are among the most common triggers. Physical health conditions such as chronic pain, respiratory problems, and hormonal changes can also disrupt sleep. Lifestyle factors, including irregular sleep schedules, excessive caffeine or alcohol use, and sedentary behavior, contribute to sleeplessness. Environmental factors such as noise, light, and temperature can play a role as well. The consequences of chronic sleeplessness extend beyond tiredness. They include impaired concentration and memory, reduced immune function, increased risk of cardiovascular and metabolic disease, and heightened vulnerability to depression and anxiety. Cognitive behavioral therapy for insomnia (CBT-I) is the most effective and recommended first-line treatment for chronic sleeplessness. It addresses the underlying thoughts and behaviors that perpetuate sleep difficulties without the risks associated with sleep medication. Medication may be appropriate for short-term use in some cases.