1 Higher doses can cause impairment of memory, judgment and coordination, irritability, paranoia,3 and suicidal thoughts. Some people experience the opposite of the intended effect, such as agitation or aggression.
Adj. 1. vertical-at right angles to the plane of the horizon or a base line; a vertical camera angle; the monument consists of two vertical pillars supporting a horizontal slab; measure the perpendicular height. perpendicular.
horizontal. 1  at right angles to the vertical; parallel to level ground. 2  flat or level: a horizontal position. 3  being in a prone or supine position; recumbent: His bad back has kept him horizontal for a week. 4  near, on, or parallel to the horizon. 5  of or relating to the horizon.