A handheld device for applying mechanical vibration to a body portion of an individual to treat a condition of the individual, includes: a housing； a cantilever beam having a first portion accommodated in the housing, and a second portion that is moveable relative to the housing, wherein the second portion is configured to apply the mechanical vibration to the body portion； and a motor in the housing, the motor configured to oscillate the second portion of the cantilever beam at an oscillation frequency.
