Introduction: Insomnia is a prevalent sleep disorder characterized by difficulty in falling asleep, maintaining sleep, or achieving restorative sleep, despite adequate opportunities. This condition often results in significant daytime impairments, including fatigue, concentration difficulties, and irritability. Insomnia can be primary or comorbid with other disorders such as anxiety or depression. Case Presentation: A 27-year-old woman presented with severe and chronic insomnia, persisting for 14 years with recent exacerbation. Her symptoms included significant difficulty in initiating and maintaining sleep, resulting in an average of only 3-4 hours of sleep per night and complete sleep deprivation for periods exceeding half an hour over the past 5 days. This sleep deficit led to pronounced emotional instability, physical discomfort, and reduced appetite, although suicidal ideation was absent. She had a past history of drug use for different psychiatric illnesses. She was started on mirtazipine 30mg and showed abrupt improvement in her symptoms. She was discharged afterwards. Discussion: The patient's chronic insomnia and its secondary effects necessitate a comprehensive treatment approach. Mirtazapine, an antidepressant with potent histamine receptor antagonism, has shown efficacy in improving sleep quality across diverse patient profiles. However, side effects like weight gain and sedation require careful monitoring. Combining mirtazapine with prolonged-release melatonin has demonstrated enhanced outcomes, particularly in perimenopausal women. Cognitive Behavioral Therapy for Insomnia (CBT-I) remains the first-line treatment due to its efficacy and long-term benefits. Conclusion: Mirtazapine can be a valuable option in the therapeutic arsenal for primary insomnia, but ongoing research is needed to refine treatment strategies. Personalized treatment plans considering patient history and response are crucial for effectively managing primary insomnia and improving patient outcomes.