Feeding/Eating, Elimination, and Sleep-Wake Disor

Why These Disorders Matter for Your Clinical Work

Picture walking into your first clinical rotation. A teenager arrives with her worried parents because she's lost 30 pounds in three months. Later, you meet with a software developer who can't sleep despite being exhausted every night. That afternoon, you consult on a case where a college student's binge eating is affecting her health and relationships. These aren't rare scenarios—feeding, eating, elimination, and sleep-wake disorders are remarkably common in clinical practice, and you'll encounter them throughout your career.

These disorders share something important: they all involve fundamental biological processes (eating, elimination, sleeping) that have gone awry in ways that seriously impact someone's health and daily functioning. Understanding them isn't just about passing the EPPP—it's about recognizing patterns you'll see regularly in practice and knowing how to help.

Understanding Feeding and Eating Disorders

Think about how much of social and professional life revolves around food. Business lunches, dinner dates, family gatherings, coffee meetings—eating is woven into nearly everything we do. When someone's relationship with food becomes distorted, it affects every aspect of their life. The DSM-5-TR defines feeding and eating disorders as persistent disturbances in eating behavior that significantly impair physical health or social functioning.

Pica: When Food Isn't Food

Pica involves persistently eating things that aren't food and have no nutritional value—paper, paint chips, coffee grounds, chalk—for at least a month. This isn't about someone absentmindedly chewing a pen cap during a stressful work deadline. We're talking about deliberate, repeated consumption that's developmentally inappropriate and not part of any cultural practice.

While pica is most common in children, you'll also see elevated rates in pregnant women. The consequences can be serious: intestinal blockages, lead poisoning from paint chips, parasitic infections. For the EPPP, remember that duration matters (one month minimum) and context matters (it must be inappropriate for the person's developmental level and culture).

Anorexia Nervosa: The Life-Threatening Pursuit of Thinness

Imagine someone looking in the mirror at a dangerously underweight body but seeing someone who needs to lose more weight. That's the distorted reality of anorexia nervosa, and it's one of the deadliest psychiatric conditions.

The three core features you need to know:

1. Significant energy restriction leading to seriously low body weight for their age, sex, and health status
2. Intense fear of weight gain or persistent behavior that prevents weight gain
3. Distorted body image or failure to recognize the severity of their low weight

Here's a critical distinction for the exam: Anorexia has two subtypes. The restricting type involves just limiting food intake and perhaps excessive exercise. The binge-eating/purging type involves episodes of binge eating or purging behaviors (like self-induced vomiting or misusing laxatives). Don't confuse this with bulimia—people with the binge-eating/purging type of anorexia are still significantly underweight.

The disorder often travels with companions—depression and anxiety disorders (especially OCD) commonly co-occur, and research suggests anxiety often shows up first, before the eating disorder develops. The medical complications are extensive because you're essentially watching the body slowly starve. Nearly every organ system gets affected: bone density decreases, heart rate slows, reproductive systems shut down, cognitive function declines.

Treatment is challenging because many people with anorexia don't believe they have a problem. Try telling someone their life-saving behavior (in their mind) is actually killing them—that's the therapeutic challenge. The immediate priority is medical stabilization and weight restoration. After that, treatment typically includes:

Three evidence-based approaches stand out:

• CBT for anorexia: Targets the core belief that weight and shape determine self-worth, works on establishing normal eating patterns, and addresses body-checking behaviors
• CBT-E (enhanced): A flexible, personalized transdiagnostic approach assuming all eating disorders share the same core problem—placing excessive value on appearance and weight
• Family-Based Treatment (FBT): For medically stable adolescents, this approach empowers parents to take charge of nutritional rehabilitation initially, then gradually returns control to the teen as they demonstrate healthier eating

Medication results have been inconsistent. Some studies show olanzapine (an antipsychotic) might help with initial weight gain, and fluoxetine (an SSRI) might support weight maintenance, but the evidence isn't strong enough for routine recommendation.

Bulimia Nervosa: The Binge-Purge Cycle

Unlike people with anorexia, most people with bulimia maintain normal or above-normal weight, which can make the disorder less visible to others. But the internal struggle is intense.

The diagnostic requirements:

The binge-purge cycle becomes like a destructive habit loop that's incredibly hard to break. Someone feels stressed or upset, binges on large amounts of food, feels guilty and panicked about weight gain, purges to compensate, experiences temporary relief, then feels shame—which often triggers the next cycle.

The medical consequences come primarily from purging behaviors. Repeated vomiting erodes tooth enamel, damages dental health, and can cause gastroesophageal reflux. More seriously, purging causes dehydration and electrolyte imbalances that can lead to cardiac arrhythmias and death. It's not as immediately life-threatening as severe anorexia, but it's still medically dangerous.

Treatment approaches mirror those for anorexia with some key differences:

• CBT and CBT-E are the go-to treatments and work well
• Interpersonal Therapy (IPT) is equally effective but takes longer to show results
• Family-Based Treatment for adolescents focuses on disrupting binging and purging while establishing healthy eating, but treatment is more collaborative than with anorexia because teens with bulimia typically experience their symptoms as ego-dystonic (distressing and inconsistent with their self-image)

Unlike with anorexia, medication shows clearer benefits. Fluoxetine (specifically at higher doses—60mg) reduces both binge eating and purging, even in people without depression.

Binge-Eating Disorder: Binging Without Purging

This is the most common eating disorder, affecting about 2-3% of adults (more women than men). Picture someone who regularly loses control around food—eating rapidly, consuming large amounts when not hungry, eating until uncomfortably full, then feeling disgusted, depressed, or guilty afterward. But unlike bulimia, there's no regular purging, excessive exercise, or fasting to compensate.

Key diagnostic points:

• Binge episodes at least once weekly for three months
• At least three characteristic symptoms (eating rapidly, eating until uncomfortably full, eating when not hungry, eating alone due to embarrassment, feeling disgusted/depressed/guilty afterward)
• Significant distress about binge eating
• No regular compensatory behaviors

Here's an important exam distinction: In binge-eating disorder, dysfunctional dieting often follows the onset of binging. In bulimia, dysfunctional dieting typically comes first. This different sequence matters for understanding and treating each disorder.

People with binge-eating disorder respond better to treatment than those with bulimia or anorexia. Both CBT-E and IPT are effective, with some studies showing CBT-E working faster. Medications (SSRIs, topiramate, lisdexamfetamine) can help but generally aren't as effective as psychotherapy alone, and combining medication with CBT doesn't improve outcomes beyond CBT alone.

One crucial treatment note: For people who are overweight or obese, experts recommend addressing the binge eating first (or at least concurrently with weight loss efforts). Trying to diet without addressing the binging pattern typically backfires.

Elimination Disorders: When Bladder Control Becomes a Clinical Issue

Enuresis means repeated urination into clothing or bedding, and we're not talking about occasional accidents. For a diagnosis, this needs to happen at least twice weekly for three consecutive months (or cause significant distress/impairment even if less frequent). The person must be at least five years old or at an equivalent developmental level.

Most cases are involuntary, and you'll specify whether it's nocturnal (during sleep), diurnal (during waking hours), or both. Nocturnal enuresis—bedwetting—is the most common type.

The moisture alarm (bell-and-pad system) is the gold standard treatment. When the child begins to urinate during sleep, moisture triggers a bell that wakes them. Over time, this conditioning helps the child wake before urination or sleep through the night without urinating. The antidiuretic medication desmopressin also works while someone takes it, but relapse rates after discontinuation are high.

Sleep-Wake Disorders: When Rest Becomes Impossible

Quality sleep is like the operating system for your brain and body—when it's not working right, everything else suffers. Sleep-wake disorders involve problems with sleep quality, timing, or amount that cause daytime distress and impairment.

Insomnia Disorder: The Exhausting Inability to Sleep

You've probably experienced occasional insomnia—lying awake before a big presentation, or waking at 3 AM with your mind racing about a relationship problem. Now imagine that happening at least three nights weekly for at least three months, despite having adequate opportunity to sleep. That's insomnia disorder.

Three types to know:

Sleep maintenance insomnia is the most common single type, but having all three types combined is actually most common overall.

Here's something fascinating: When researchers compare what people with insomnia report about their sleep versus objective polysomnography measurements, there's a consistent pattern of mismatch. People overestimate how long it takes to fall asleep, overestimate time spent awake during the night, and underestimate total sleep time. Their subjective experience is genuinely distressing, but it doesn't fully match the objective reality. This matters for treatment planning.

Cognitive-Behavioral Therapy for Insomnia (CBT-I) is considered the first-line treatment—and for good reason. It's a multi-component approach targeting nighttime processes:

1. Stimulus control: Strengthening the bedroom and bed as cues for sleep. Go to bed only when sleepy, use the bedroom only for sleep (and sex), leave the bedroom if unable to fall asleep within 20 minutes.

2. Sleep restriction: Improving sleep efficiency (the percentage of time in bed actually spent sleeping). Initially restrict time in bed to match actual current sleep time, then gradually increase as efficiency improves. This creates mild sleep deprivation that makes falling asleep easier.

3. Sleep hygiene: Education about behaviors that help and hurt sleep—comfortable bedroom environment, limiting caffeine, avoiding clock-watching.

4. Relaxation training: Progressive muscle relaxation, meditation, breathing exercises to reduce physiological arousal.

5. Cognitive restructuring: Identifying and replacing anxiety-provoking thoughts about sleep ("If I don't sleep tonight, I'll fail my presentation tomorrow").

Cognitive Therapy for Insomnia (CT-I) is based on Harvey's model and targets cognitive processes operating both day and night:

• Sleep-related worry and rumination that increase arousal
• Selective attention to sleep-related threats (monitoring for fatigue and concentration problems)
• Unhelpful beliefs about sleep and its consequences
• Misperceptions about actual sleep versus perceived sleep
• Safety behaviors that paradoxically worsen insomnia (like exercising before bed to tire yourself out, drinking alcohol to fall asleep, avoiding evening activities to "save energy")

Narcolepsy: When Sleep Attacks Disrupt Life

Imagine being in the middle of an important work meeting when an irresistible need to sleep overcomes you. That's narcolepsy—recurrent, uncontrollable sleep attacks occurring at least three times weekly for three months or more.

The diagnosis requires one of three additional features:

1. Cataplexy: Sudden loss of muscle tone, often triggered by strong emotions (laughing at a joke and your knees buckle)
2. Hypocretin deficiency: Low levels of this wake-promoting brain chemical
3. REM sleep latency of 15 minutes or less: Measured by polysomnography

Many people with narcolepsy also experience hypnagogic hallucinations (vivid hallucinations when falling asleep) or hypnopompic hallucinations (when waking up), plus sleep paralysis—being temporarily unable to move when falling asleep or waking up. Because strong emotions often trigger cataplexy, some people learn to suppress their emotions, which creates its own problems.

Treatment combines behavioral strategies (good sleep habits, scheduled naps, staying active) with medications. For alertness: modafinil/armodafinil or stimulants like methylphenidate. For cataplexy: antidepressants like venlafaxine or fluoxetine. Sodium oxybate works for patients who don't respond to other treatments, improving nighttime deep sleep while reducing daytime sleepiness and cataplexy.

Non-REM Sleep Arousal Disorders: Sleepwalking and Sleep Terrors

These both involve incomplete awakening from deep sleep (Stages 3-4), usually in the first third of the night.

Sleepwalking involves getting out of bed and walking around during sleep. Some people engage in complex behaviors like sleep-eating or even sleep-driving. The person is difficult to awaken, and upon waking has little or no memory of the episode.

Sleep terrors involve abruptly waking from sleep with a panicky scream, intense fear, and autonomic arousal (racing heart, rapid breathing, sweating). Unlike nightmares, the person doesn't remember dream content and can't recall the episode. They're unresponsive to comfort attempts during the episode.

Both conditions are more common in childhood and typically decrease with age. They're not usually signs of serious psychopathology in children, though adult-onset cases warrant more careful evaluation.

Nightmare Disorder: When Bad Dreams Become a Clinical Problem

Everyone has nightmares occasionally, but nightmare disorder involves repeated, extremely distressing dreams that are well-remembered and typically involve threats to survival, security, or physical integrity. These occur during REM sleep, usually in the second half of the night.

The key distinction from sleep terrors: People wake from nightmares oriented and alert but may continue feeling upset. They remember the dream content vividly. In sleep terrors, people don't remember dream content and are confused upon awakening.

Common Mistakes Students Make

Confusing the eating disorders: Remember—anorexia involves significantly low weight. If someone's normal weight and purging, that's bulimia. If they're binging without compensatory behaviors, that's binge-eating disorder. Weight status is your first sorting criterion.

Mixing up sleep disorders: Insomnia is difficulty sleeping despite opportunity. Narcolepsy is uncontrollable sleep attacks with specific additional features (cataplexy, hypocretin deficiency, or REM latency). Sleep terrors happen in deep non-REM sleep without dream recall; nightmares happen in REM sleep with vivid recall.

Forgetting frequency and duration requirements: Most of these disorders have specific timeframes. Anorexia and bulimia require behaviors at least weekly for three months. Same with binge-eating disorder. Enuresis requires at least twice weekly for three months. Get these numbers down cold.

Overlooking the treatment distinctions: CBT-I is first-line for insomnia. Family-based treatment works for adolescent anorexia and bulimia but looks different for each. Medications help bulimia but have inconsistent results for anorexia. These specifics show up on the exam.

Practice Tips for Remembering

Create a comparison table for the eating disorders in your notes. List anorexia, bulimia, and binge-eating disorder across the top, then compare features like weight status, presence of binging, presence of compensatory behaviors, and first-line treatments. The visual comparison makes differences clearer.

Use the acronym "NITE" for CBT-I components: Nighttime strategies (stimulus control), Improve efficiency (sleep restriction), Training (relaxation and sleep hygiene), Exchange thoughts (cognitive restructuring).

Remember "REM = Remember": REM sleep disorders (nightmares) involve remembering dreams. Non-REM disorders (sleep terrors, sleepwalking) involve not remembering.

Link disorders to the biological process: Eating disorders cluster together but have different features. Sleep disorders cluster together but have different features. Thinking categorically helps your brain organize the information.

Practice distinguishing scenarios: Create flashcards with brief case descriptions and practice identifying the correct disorder. "22-year-old woman, BMI 16, refuses to eat more, sees herself as fat" = anorexia, restricting type. "19-year-old man, normal weight, binges twice weekly then vomits" = bulimia. The more you practice sorting, the more automatic it becomes.

Key Takeaways

• Anorexia nervosa requires significantly low weight, fear of weight gain, and distorted body image; has restricting and binge-eating/purging subtypes; carries high mortality risk

• Bulimia nervosa involves recurrent binge eating with compensatory behaviors (at least weekly for 3+ months), normal or elevated weight, and serious medical complications from purging

• Binge-eating disorder includes binge eating without regular compensatory behaviors, occurs at least weekly for 3+ months, and generally has better treatment outcomes than anorexia or bulimia

• CBT-E is a transdiagnostic treatment assuming all eating disorders share core psychopathology around excessive value placed on appearance and weight

• Enuresis requires repeated urination into bed or clothing at least twice weekly for 3+ months in someone age 5+; moisture alarm is first-line treatment

• Insomnia disorder involves difficulty with sleep initiation, maintenance, or early awakening at least 3 nights weekly for 3+ months; CBT-I is first-line treatment with multiple components

• Narcolepsy involves irrepressible sleep attacks requiring cataplexy, hypocretin deficiency, or rapid REM latency for diagnosis; treated with behavioral strategies plus medications

• Sleep terrors occur in non-REM sleep without dream recall; nightmares occur in REM sleep with vivid dream recall

• Treatment approaches vary significantly across disorders—know which therapies work best for which conditions and whether medications add value

• Duration and frequency criteria matter for accurate diagnosis—these specific timeframes appear regularly on the EPPP