Interestingly enough, there are many similarities between ADHD and bipolar syndrome which should be recognized when attempting to diagnose a child behavior.
Both ADHD and Bipolar share similar characteristics such as impulsivity, inattention, hyperactivity, sudden behavior changes, defiant conduct, and learning problems. Many experience motor restlessness at night (this occurs to bipolar children when in a "manic" phase).
In many cases, psychostimulants or antidepressants can be prescribed to treat both disorders. For this reason, in many cases, it is hard to tell these conditions apart.
So, how can you tell the difference? Well, for one, when it comes to destructiveness, an ADHD child will break things carelessly while playing while the bipolar individual breaks things as a result of anger. Children who are bipolar may exhibit severe temper tantrums where they release manic quantities of emotional and physical energy, sometimes with violent results.
The duration of the outburst will also tend to be longer with children who are bipolar, lasting for over 30 minutes to up to 2-4 hours. An ADHD child, on the other hand, generally calms down withn 20-30 minutes.
Tantrums by bipolar children are generally triggered by limit-setting conflicts with authority figures, whereas ADHD are fueled by sensory and overstimulation.
It should also be noted that children with bipolar disorder exhibit intentional misbehavior, such as crashing into a wall on purpose while a child with ADHD may crash into the wall accidentally. The same thing goes for fighting – an ADHD child may inadvertently get into a fight while the bipolar child looks for the fight and the power struggle that goes along with it.