Insomnia: Acute and Chronic, Diagnosis, CBT-I, and Pharmacotherapy

Introduction

Insomnia is the most common sleep disorder, characterized by difficulty initiating or maintaining sleep, or early morning awakening, despite adequate opportunity for sleep, accompanied by daytime functional impairment. Chronic insomnia affects approximately 6-10% of adults, with transient insomnia affecting 30-50% annually. It is more common in women, older adults, and those with medical or psychiatric comorbidities.

Classification

Acute vs Chronic Insomnia

Feature	Acute (Short-term) Insomnia	Chronic Insomnia
Duration	<3 months	3 months or longer
Frequency	Variable	3+ nights per week
Prevalence	15-30% annually	6-10%
Trigger	Usually identifiable stressor	Often multifactorial (may persist after trigger resolves)
Treatment focus	Address trigger, sleep hygiene, brief intervention	CBT-I, pharmacotherapy as adjunct
Prognosis	Usually resolves when stressor resolves	May persist without treatment

Insomnia Subtypes

Subtype	Description
Sleep onset insomnia	Difficulty falling asleep (>30 min to fall asleep)
Sleep maintenance insomnia	Difficulty staying asleep (prolonged or frequent awakenings)
Late insomnia (early morning awakening)	Waking earlier than desired and unable to return to sleep
Mixed insomnia	Combination of two or more types
Paradoxical insomnia (sleep state misperception)	Subjective complaint of poor sleep without objective evidence
Psychophysiological insomnia	Conditioned arousal related to sleep environment/bedtime
Idiopathic insomnia	Lifelong inability to obtain adequate sleep (childhood onset, no clear cause)
Comorbid insomnia	Insomnia associated with another medical, psychiatric, or sleep disorder

Diagnostic Criteria

DSM-5 Criteria for Insomnia Disorder

Criterion	Description
A	Predominant complaint of dissatisfaction with sleep quantity or quality, with one or more: difficulty initiating sleep, maintaining sleep, or early morning awakening
B	Sleep disturbance causes clinically significant distress or impairment (social, occupational, educational, behavioral, or other)
C	Sleep difficulty occurs at least 3 nights per week
D	Sleep difficulty present for at least 3 months
E	Sleep difficulty occurs despite adequate opportunity for sleep
F	Insomnia is not better explained by another sleep-wake disorder
G	Insomnia is not attributable to physiological effects of a substance
H	Coexisting mental health or medical conditions do not adequately explain insomnia

ICSD-3 Diagnostic Criteria

Criterion	Description
A	Report of sleep initiation or maintenance problems, early morning awakening, or resistance to going to bed (children)
B	Report of at least one daytime symptom: fatigue, attention/memory impairment, mood disturbance, irritability, daytime sleepiness, motivation/initiative reduction, errors/accidents proneness, concerns about sleep, behavior problems (children)
C	Not explained by inadequate sleep opportunity or environment
D	Frequency: 3+ times per week
E	Duration: 3+ months
F	Not better explained by another disorder

Insomnia Severity Index (ISI)

Score	Severity
0-7	No clinically significant insomnia
8-14	Subthreshold insomnia
15-21	Clinical insomnia (moderate severity)
22-28	Clinical insomnia (severe)

Pathophysiology

The 3-P Model of Insomnia

Factor	Description	Examples
Predisposing	Factors that increase vulnerability to insomnia	Female sex, older age, perfectionism, anxiety trait, family history
Precipitating	Events that trigger the onset of insomnia	Stress (work, relationship, health), trauma, illness, medication change
Perpetuating	Behaviors that maintain insomnia after trigger resolves	Spending too much time in bed, napping, clock-watching, catastrophic thinking, sleep aids

Hyperarousal in Insomnia

System	Finding
HPA axis	Increased cortisol throughout day and night
Autonomic nervous system	Increased heart rate, reduced heart rate variability
Metabolic rate	Increased 24-hour metabolic rate
EEG	Increased high-frequency activity (beta, gamma) during sleep
Neuroimaging	Increased activity in arousal-promoting regions (thalamus, hypothalamus, brainstem)

Cognitive Behavioral Therapy for Insomnia (CBT-I)

Overview

Component	Description	Effect Size
Stimulus control	Strengthen bed-sleep association	Large
Sleep restriction	Consolidate sleep by limiting time in bed	Large
Cognitive restructuring	Address maladaptive beliefs about sleep	Moderate
Sleep hygiene education	Optimize environment and habits	Small (supportive)
Relaxation training	Reduce physiological arousal	Moderate
Relapse prevention	Maintain gains after treatment	Long-term efficacy

Stimulus Control Therapy

Instruction	Rationale
Go to bed only when sleepy	Associate bed with sleepiness, not frustration
Use bed only for sleep and sex	Break association between bed and wakeful activities
If unable to sleep within 20 minutes, get out of bed	Break association between bed and wakefulness
Return to bed only when sleepy again	Rebuild bed-sleep pairing
Keep consistent wake time every day (7 days/week)	Stabilize circadian rhythm
No napping during the day	Consolidate nighttime sleep pressure

Sleep Restriction Therapy

Step	Action
1	Keep sleep diary for 1-2 weeks to establish baseline
2	Calculate average total sleep time (TST) from diary
3	Prescribe initial time in bed = TST + 30 minutes (minimum 5 hours)
4	Set fixed wake time based on typical schedule
5	Calculate bedtime = wake time minus prescribed time in bed
6	Week 1: follow prescribed sleep window
7	Calculate sleep efficiency (TST / time in bed x 100)
8	If SE >85%, increase time in bed by 15-30 minutes
9	If SE <85%, hold window same or reduce further
10	Continue adjusting until optimal sleep duration achieved (usually 7-8 hours)

Sleep Efficiency Targets

Sleep Efficiency	Interpretation	Action
>90%	Very good	May be ready for maintenance
85-89%	Good	Consider slight increase in time in bed
80-84%	Moderate	Hold time in bed for another week
<80%	Poor	Consider reducing time in bed by 15-30 minutes

Cognitive Restructuring

Maladaptive Belief	Challenged Thought	Alternative Belief
“I will never fall asleep”	That’s catastrophic thinking; I have fallen asleep every night of my life	“Even if I sleep poorly, I can still function tomorrow”
“I need 8 hours of sleep or I will fall apart”	Sleep needs vary; 7 hours is adequate for many	“I function better with 7 hours than lying awake worrying”
“If I don’t sleep well, I will be useless tomorrow”	One night of poor sleep does not define my ability	“I have functioned before on less sleep; I can do it again”
“It’s hopeless, nothing works”	CBT-I has 70-80% efficacy; this is treated process	“This is a skill I am learning; it takes time”

Relaxation Training

Technique	Description	Instructions
Progressive muscle relaxation	Systematic tension and release of muscle groups	Tense each muscle for 5 seconds, relax for 10 seconds, move from feet to head
Diaphragmatic breathing	Slow, deep abdominal breathing	Inhale through nose for 4 counts, exhale through mouth for 6 counts
Guided imagery	Visualize calming scene	Imagine a peaceful, detailed setting engaging all senses
Mindfulness meditation	Non-judgmental awareness of present moment	Focus on breath; when mind wanders, gently return to breath
Autogenic training	Self-suggestion of heaviness and warmth	“My right arm is heavy… warm… heavy and warm…”

Pharmacotherapy for Insomnia

First-Line Medications (Non-Benzodiazepine Hypnotics)

Drug	Half-life	Onset	Dose (mg)	Indication	Side Effects
Zolpidem (Ambien)	2.5-3 hours	Rapid	IR: 5-10; ER: 6.25-12.5; Intermezzo (SL): 1.75-3.5	Sleep onset, sleep maintenance (ER)	Dizziness, drowsiness, amnesia, complex sleep behaviors
Zaleplon (Sonata)	1 hour	Very rapid	5-20	Sleep onset only	Short duration limits efficacy for maintenance
Eszopiclone (Lunesta)	5-7 hours	Rapid	1, 2, 3	Sleep onset and maintenance	Unpleasant taste (17%), dizziness, headache
Zopiclone (Imovane)	5 hours	Rapid	3.75-7.5	Sleep onset, maintenance	Bitter/metallic taste, morning sedation

Off-Label and Second-Line Medications

Drug	Class	Dose for Insomnia	Side Effects	Concerns
Trazodone	SARI	25-100 mg at bedtime	Drowsiness, orthostasis, priapism	Most commonly prescribed off-label for insomnia
Doxepin (Silenor)	TCA	3-6 mg	Dry mouth, sedation	FDA-approved for sleep maintenance
Amitriptyline	TCA	10-50 mg	Anticholinergic, weight gain, QTc prolongation	Used for pain + insomnia
Mirtazapine (Remeron)	NaSSA	7.5-30 mg	Weight gain, sedation	Dose-dependent anti-histamine effect
Gabapentin	Gabapentinoid	100-600 mg	Dizziness, sedation	Used for insomnia + neuropathic pain
Quetiapine (Seroquel)	Atypical antipsychotic	25-100 mg	Weight gain, metabolic syndrome	High-risk; avoid as first-line
Diphenhydramine	Antihistamine	25-50 mg	Anticholinergic, tolerance develops	Tolerance in 3-7 days; avoid in elderly
Melatonin	Hormone	0.5-5 mg	Minimal	Best for circadian disorders, not primary insomnia
Ramelteon (Rozerem)	Melatonin receptor agonist	8 mg	Minimal	No abuse potential; good for sleep onset
Suvorexant (Belsomra)	Orexin antagonist	10-20 mg	Morning sedation, narcolepsy-like effects	Novel mechanism; no abuse potential

Melatonin Receptor Agonists

Drug	Mechanism	Onset	Half-life	Advantages	Disadvantages
Melatonin (OTC)	MT1/MT2 agonist	Variable	30-60 min	Readily available, safe	Variable potency, purity concerns
Ramelteon (Rozerem)	MT1/MT2 agonist	~60 min	1-2.6 hours	FDA-approved, no abuse potential	Expensive, modest effect
Tasimelteon (Hetlioz)	MT1/MT2 agonist	~60 min	1-2 hours	Non-24 disorder (blind)	Expensive, limited indications

Orexin Receptor Antagonists

Drug	Mechanism	Half-life	Dosing	Side Effects
Suvorexant (Belsomra)	Dual orexin receptor antagonist (DORA)	12 hours	10-20 mg	Next-day somnolence, possible narcolepsy-like effects
Daridorexant (Quviviq)	DORA	8 hours	25-50 mg	Similar to suvorexant; fewer next-day effects
Lemborexant (Dayvigo)	DORA	17-19 hours	5-10 mg	Next-day somnolence at higher doses

Benzodiazepine Hypnotics

Drug	Half-life	Onset	Dose (mg)	Indication	Concerns
Temazepam (Restoril)	8-15 hours	Intermediate	7.5-30	Sleep maintenance	Daytime sedation, fall risk
Triazolam (Halcion)	2-5 hours	Rapid	0.125-0.25	Sleep onset	Amnesia, dependence
Estazolam	10-24 hours	Rapid	0.5-2	Sleep onset, maintenance	Daytime sedation
Flurazepam	47-100 hours (active metabolite)	Rapid	15-30	Sleep maintenance	Long half-life, accumulation, fall risk

Benzodiazepine Receptor Agonist Comparison

Property	Zolpidem	Zaleplon	Eszopiclone	Temazepam
t1/2 (hours)	2.5-3	1	5-7	8-15
Best for onset	Yes	Yes	Yes	No (intermediate onset)
Best for maintenance	ER only	No	Yes	Yes
Rebound on discontinuation	Mild	Mild	Mild	Moderate
Tolerance development	Moderate	Low	Moderate	Moderate-high
Abuse potential	Moderate	Low	Moderate	Moderate
Complex sleep behaviors	Reported (higher risk with high dose)	Rare	Reported	Rare

Guideline Recommendations for Pharmacotherapy

Organization	First-Line	Second-Line	Avoid
AASM (2017)	Suvorexant, Ramelteon, Zolpidem, Eszopiclone, Temazepam	Trazodone, Doxepin	Diphenhydramine, Melatonin (for primary insomnia)
ACP (2016)	CBT-I first; discuss pharmacotherapy as adjunct	Z-drugs, benzodiazepines, ramelteon, doxepin, suvorexant	Antipsychotics (quetiapine)

Special Populations

Insomnia in Elderly

Consideration	Recommendation
First-line treatment	CBT-I (modified for sensory/cognitive needs)
Medication caution	Lower doses; avoid anticholinergics, long-acting benzodiazepines
BEERS criteria	Avoid benzodiazepines, anticholinergics, barbiturates in elderly
Preferred agents	Ramelteon, low-dose doxepin (3-6 mg)
Medical review	Identify and treat underlying causes (pain, nocturia, RLS, medication side effects)

Insomnia in Pregnancy

Trimester	Approach
First	Non-pharmacologic (CBT-I), sleep hygiene, positioning
Second	Continue non-pharmacologic; diphenhydramine (Category B) cautiously
Third	CBT-I, positioning (left lateral), treats acid reflux, RLS
Postpartum	Sleep when baby sleeps, support network, treat depression

Insomnia in Children

Age	Approach
Infants	Bedtime routine, parent education, graduated extinction
Toddlers	Consistent routine, limit setting, transitional object
School-age	Sleep hygiene, stimulus control, treat anxiety
Adolescents	Delayed phase common; combined CBT-I + chronotherapy, limit screens

Long-Term Management

Relapse Prevention

Strategy	Description
Periodic sleep diary	Monitor sleep pattern 1 week per month
Maintain circadian rhythm	Consistent wake time 7 days/week
Manage stressors	Ongoing stress management techniques
Booster sessions	CBT-I refresher if symptoms return
Recognize early signs	Brief intervention at first sign of relapse
Medications	If using, use as needed rather than nightly to minimize tolerance