What causes a 15-month-old child to have trouble falling asleep and staying asleep?

Sleep Difficulties in a 15-Month-Old Child

A 15-month-old with sleep difficulties most likely has behavioral insomnia of childhood, which requires establishing a consistent bedtime routine and addressing inappropriate sleep-onset associations as first-line treatment. 1, 2, 3

Common Causes at This Age

Sleep problems affect approximately 25-50% of young children and stem from multiple factors 4, 5:

• Behavioral insomnia of childhood is the most common cause, characterized by a learned inability to fall asleep independently or return to sleep after normal night wakings 5, 6
• Inappropriate sleep-onset associations, such as needing to be held, rocked, or fed to fall asleep, prevent the child from self-soothing when they experience normal arousals during the night 2, 6
• Lack of consistent bedtime routines disrupts the child's ability to recognize sleep cues and transition to sleep 1, 7
• Poor sleep hygiene, including irregular sleep schedules, overstimulation before bed, or excessive screen time exposure 4, 8

Medical Contributors to Rule Out

Before implementing behavioral interventions, evaluate for underlying medical issues that can disrupt sleep 9:

• Gastrointestinal disorders (reflux, constipation causing discomfort) 9
• Pain from any source (ear infections, teething) 9
• Primary sleep disorders including sleep-disordered breathing (snoring, apnea) and restless legs symptoms 9, 5
• Nutritional deficiencies, particularly iron deficiency 9, 5
• Medications that may interfere with sleep 9

First-Line Treatment Approach

Behavioral interventions are the standard of care and should be implemented before considering any medication. 1, 2, 3

Establish a Consistent Bedtime Routine

• Implement a predictable sequence of calming activities (bath, book, song) performed in the same order at the same time every night, which reduces insomnia with an effect size of 0.67 1, 3
• Fix both bedtime and wake time to the same schedule every day, including weekends 1, 3
• Use visual schedules showing the bedtime routine steps, which helps toddlers understand expectations and reduces anxiety 1, 3

Address Sleep-Onset Associations

• Place the child in the crib drowsy but awake, not fully asleep, so they learn to fall asleep independently 2, 8
• Use graduated extinction: if the child cries, check at systematically increasing intervals (e.g., 3,5,10 minutes) with brief verbal reassurance without picking up 2, 8
• Expect improvements within 3 nights to 4 weeks with proper implementation 2, 8

Optimize Sleep Environment

• Ensure the room is dark, quiet, and at a comfortable temperature 4, 8
• Remove all soft bedding, toys, and ensure a firm sleep surface for safety 2
• Limit screen exposure, especially in the 1-2 hours before bedtime 4

Parent Education and Support

• Provide hands-on instruction about proper implementation of behavioral strategies, as success depends heavily on consistent parental follow-through 1, 3
• Have parents maintain a sleep diary for 1-2 weeks documenting bedtime, wake time, sleep onset latency, number and duration of night wakings 1, 2

When to Consider Pharmacological Treatment

Melatonin is the only evidence-based pharmacological option for children over 2 years old if behavioral interventions fail. 1, 3

• Start with 1 mg given 30-60 minutes before bedtime 1, 3
• Melatonin reduces sleep onset latency by 16-60 minutes with an effect size of 1.7 1, 3
• It has the strongest evidence base and safest profile for pediatric insomnia 9, 1, 3
• However, at 15 months, behavioral interventions should be exhausted first, and melatonin is generally reserved for children 2 years and older 1, 3

Follow-Up and Monitoring

• Schedule follow-up within 2-4 weeks after initiating behavioral interventions to review the sleep diary and assess progress 1, 2, 3
• Expect to see meaningful improvements within 4 weeks if interventions are properly implemented 2, 3
• If no improvement occurs after 4 weeks of consistent behavioral intervention, reassess the diagnosis and consider referral to a pediatric sleep specialist 2, 3

Critical Pitfalls to Avoid

• Do not start with medication when behavioral interventions have strong evidence and avoid medication side effects 3
• Do not implement behavioral strategies without adequate parent education, as this leads to inconsistent application and treatment failure 1, 3
• Do not overlook medical contributors like sleep-disordered breathing or gastrointestinal issues that require specific treatment 9, 5
• Do not allow the child to fall asleep in locations other than their crib (parent's bed, while feeding), as this creates problematic sleep-onset associations 2, 6

When to Refer to a Sleep Specialist

Refer if 1, 2, 3:

• No improvement after 4 weeks of properly implemented behavioral interventions 2, 3
• Suspected primary sleep disorder (snoring, witnessed apneas, restless legs symptoms) 1, 3, 5
• Severe insomnia causing significant daytime impairment or safety concerns 1, 3