What does an increased adh (vasopressin) cause?

Reduced urine output: Free water retention with resulting volume expansion and reduced electrolyte concentrations.

Low sodium: ADH (vasopressin) is anti-diuretic hormone which causes your body to retain free water. When you have too much of it, your body retains too much free water and "dilutes" out the sodium content in your blood which will cause the level to drop. Low sodium in the blood can be very detrimental to your health.