Bipolar disorders usually present as alternating episodes of melancholy and mania. However, other clinical situations appear in a masked form before being spotted. The principal one is hypomania that declares itself as an attenuated form of a manic episode. Its principal signs are an increase in energy, hyperactivity and disinhibition. In other cases, bipolar disorders express themselves as impulsive behaviours. More rarely, the mask of a bipolar illness is translated into behaviours such as intermittent alcohol abuse. The consummation of alcohol is sudden and paroxysmal. It is a type of dipsomania. Finally, bipolar disorders can express themselves as difficulty in impulse control. The two most frequent examples are impulse buying and pathological gambling.