What Causes Erectile Dysfunction?

Erectile dysfunction (ED) is a multifactorial condition with diverse underlying causes, broadly categorized as organic, psychological, or mixed. Organic causes—accounting for the majority of cases in men over 50—include vascular insufficiency (e.g., atherosclerosis, hypertension, or diabetes-related endothelial dysfunction), neurological disorders (such as multiple sclerosis, Parkinson disease, spinal cord injury, or diabetic neuropathy), hormonal imbalances (notably hypogonadism, hyperprolactinemia, or thyroid dysfunction), and structural abnormalities (including Peyronie disease or post-prostatectomy fibrosis). Medications—including antihypertensives (e.g., beta-blockers, thiazides), antidepressants (particularly SSRIs), antipsychotics, and opioids—represent a common iatrogenic contributor.

Psychological factors, more prevalent in younger men with sudden-onset ED and preserved nocturnal erections, encompass performance anxiety, depression, chronic stress, relationship conflict, and past sexual trauma. These often coexist with organic contributors, resulting in mixed etiology—a scenario encountered in up to 80% of clinical cases.

Additional contributing elements include lifestyle factors such as smoking, excessive alcohol consumption, sedentary behavior, obesity, and sleep apnea; pelvic surgery or radiation therapy; and chronic systemic conditions like chronic kidney disease or heart failure. A thorough evaluation—including detailed history, physical examination, serum testosterone and prolactin testing, and, when indicated, penile Doppler ultrasound or nocturnal penile tumescence monitoring—is essential to guide evidence-based management.