Metaphorical models - Bipolar Disorders
The Loose Switch Metaphor
Having bipolar disorder is like having a loose emotional switch. Flick the switch up and mood becomes elevated, flick down and mood becomes depressed. The switch tends to flick from north pole to south, or between black and white, without any shades of grey. It is as if there is an absence or a diminution of any inhibitory process to prevent the emotional momentum from building in a particular direction.
(Mood stabiliser) medication is like using glue to stiffen the switch, discouraging the switch from flicking to one pole, and discouraging mood instability.