A small carriage propelled by a steam turbine powered engine was apparently invented by Ferdinand Verbiest, a Belgian, in 1672 while in China. It is argued that this constitutes the first 'car' ever invented, but the design was only 65cm long, had no seats or pilot controls, and was intended as little more than a toy.
In bipolar disorder, mixed state is a condition during which symptoms of both mania and depression occur simultaneously. Individuals experiencing a mixed state may have manic symptoms such as grandiose thoughts while simultaneously experiencing depressive symptoms such as excessive guilt or feeling suicidal.
These symptoms describe a wide range of physical and mental disorders, however, including depression and attention deficit hyperactivity disorder (ADHD). Bipolar disorder symptoms in adolescents resemble those experienced by bipolar adults, including cycles between mania and depression. However, unlike adults, adolescents may experience these severe mood swings multiple times in a day or a week. Many bipolar teenage girls experience their first episode in conjunction with their first period.