In a male patient with generalized anxiety disorder on buspirone, slightly low serum testosterone, normal early‑morning erections, and no vascular risk factors, what is the most likely cause of his difficulty maintaining an erection: buspirone, hypogonadism, psychogenic, or vascular disease?

Most Likely Cause: Psychogenic Erectile Dysfunction

The most likely cause of this patient's erectile dysfunction is psychogenic, specifically related to his generalized anxiety disorder. The preserved early morning erections several days per week are the key diagnostic finding that strongly indicates a psychogenic rather than organic etiology 1, 2.

Clinical Reasoning

Why Psychogenic ED is Most Likely

• The presence of morning/nocturnal erections is the critical distinguishing feature that suggests psychogenic ED, as these spontaneous erections indicate intact neurovascular mechanisms 1, 2.
• Psychogenic ED typically presents with sudden onset, preserved spontaneous erections, and situational variability—all consistent with this patient's presentation 3, 4.
• Generalized anxiety disorder is a well-established psychological cause of ED, with anxiety being one of the primary psychogenic contributors alongside depression 5, 6.
• The patient's lack of vascular risk factors (no smoking, no alcohol) makes vasculogenic ED less likely 1, 3.

Why Other Options Are Less Likely

Buspirone:

• While many psychotropic medications cause ED, buspirone is actually associated with lower rates of sexual dysfunction compared to SSRIs and other anxiolytics 2.
• If buspirone were the primary cause, you would expect loss of all erections (including morning erections), not selective situational ED 1.

Hypogonadism:

• A testosterone level of 285 ng/dL is only marginally below the 300 ng/dL threshold for hypogonadism 1, 2.
• Hypogonadism typically presents with loss of libido as the predominant symptom, which is not mentioned in this case 2, 3.
• Men with pure hypogonadism usually experience gradual onset and loss of morning erections, not preserved spontaneous erections 1, 4.
• The borderline testosterone level alone, without accompanying symptoms of low libido or other hypogonadal features, does not explain the clinical picture 1.

Vascular Disease:

• Vasculogenic ED presents with gradual onset and progressive loss of all erections, including morning erections 1, 3, 4.
• This patient has no cardiovascular risk factors (no smoking, no alcohol, no mentioned diabetes/hypertension/hyperlipidemia) 1, 3.
• The preservation of morning erections essentially rules out significant vascular insufficiency as the primary cause 1, 2.

Diagnostic Confirmation

• The pattern of situational ED with preserved spontaneous erections is pathognomonic for psychogenic etiology 1, 3.
• Performance anxiety related to generalized anxiety disorder is the most parsimonious explanation for this clinical presentation 5, 6.

Management Implications

• First-line treatment should combine psychosexual counseling with PDE5 inhibitors, as this combination yields superior outcomes compared to either modality alone 2, 3, 5.
• Referral to a mental health professional is recommended to address the underlying anxiety disorder and reduce performance anxiety 1, 2.
• The borderline testosterone does not require immediate replacement therapy in the absence of hypogonadal symptoms, though it could be rechecked 1, 2.