What causes Anorexia?
Last updated September 7, 2026.
Anorexia nervosa has no single cause; it develops when inherited biology, brain and hormone differences, personality traits, and social pressures act together. In everyday medical use, "anorexia" alone means loss of appetite from illness or medication, while anorexia nervosa is an eating disorder driven by restriction and fear of weight gain. Family and twin studies show that risk runs in families, and traits like perfectionism, anxiety, and rigid thinking make restriction feel rewarding rather than distressing. Common triggers include dieting, puberty, weight-related comments, stressful life changes, trauma, and sports or jobs that emphasize a lean body. Once weight loss starts, starvation itself alters brain chemistry, mood, and thinking, which keeps the cycle running and makes willpower explanations wrong. Eating regular meals, limiting appearance-focused social media, and talking early with a clinician or dietitian help interrupt the pattern before it becomes entrenched.
What to do
- Separate the two meanings: Ask whether you mean lost appetite from an illness or medication, or anorexia nervosa, because the causes and care differ.
- Look at family history: Eating disorders, depression, anxiety, and substance use in close relatives raise risk and are worth telling your clinician.
- Track the trigger: Note when restriction started, such as after a diet, a growth spurt, a comment about weight, or a stressful event.
- Check medical causes of appetite loss: Thyroid disease, infections, depression, cancer, and drugs like stimulants, opioids, and some antibiotics can cut appetite.
- Restore regular eating first: Three meals and two snacks a day helps reverse starvation effects on mood and thinking while you arrange treatment.
- Get urgent care for danger signs: Fainting, chest pain, irregular heartbeat, vomiting blood, confusion, or rapid weight loss need same-day medical review.
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