depending on the clinician’s assessment of their relevance given the individual’s age, co-
morbid medical problems, and clinical pres entation. Doppler ultrasonography and intra-
vascular injection of vasoactive drugs, as we ll as invasive diagnostic procedures such as
dynamic infusion cavernosography, can be used to assess vascular integrity. Pudendal
nerve conduction studies, including somato sensory evoked potentials, can be employed
when a peripheral neuropathy is suspected. In men also complaining of decreased sexual
desire, serum bioavailable or free testosterone is frequently assessed to determine if the
difficulty is secondary to endocrinological factors. Thyroid function may also be assessed.
Determination of fasting serum glucose is useful to screen for the pres ence of diabetes mel-
litus. The assessment of serum lipids is important, as erectile disorder in men 40 years and
older is predictive of the future risk of coronary artery disease.
Functional Consequences  of Erectile Disorder
Erectile disorder can interfere with fertility and produce both indivi dual and interpersonal
distress. Fear and/or avoidance of sexual en counters may interfere with the ability to de-
velop intimate relationships.
Differential Diagnosis
Nonsexual mental disorders. Major depressive disorder and erectile disorder are closely
associated, and erectile diso rder accompanying severe de pressive disorder may occur.
Normal erectile function. The differential should include consideration of normal erec-
tile function in men with  excessive expectations.