Consider the following:
Decreased sleep: as in I “can’t sleep” versus “don’t need to sleep”.
Ruminative thinking versus racing thoughts. “Can’t turn off my thinking” versus “thinking too fast to put it in words”. Remember: the speed of thought is essential.
Distractibility versus tangentiality. “Mind going blank, cant remember what I was thinking/talking about” versus “thoughts just pop up, one after another”.
Psychomotor agitation: the patient reports feeling exhausted but restless as in “I can’t stop worrying” versus hyperenergetic.
Impulsivity: as in “I wanted to kill myself as I can no longer stand feeling this way” or “I don’t think much about what to do next.”
Same or different?
When it comes to psychiatric history and review of systems the context is what makes or brakes your diagnosis.
Which, in the cases above, should be depression versus mania.
1. Course: ADHD is chronic versus bipolar: episodic. Which also means that you should see ADHD signs during exam, while we might or might not see signs of bipolar on presentation.
2. Long time prognosis: ADHD might get better with time while bipolar tends to get worse with time.
3. Drugs of abuse: ADHD: “cocaine (in general uppers) slow me down”. Bipolar: “I use uppers when I am down, downers when I am hyper”.
4. Family history: bipolar patients have more of a loaded fam hx in terms of affective and psychotic disorders.
5. When in doubt, safety comes first: assume and treat as bipolar (i.e. mood stabilizer) as while this will help a bipolar patient; at the same time, it might not help it would also not harm an ADHD patient. Stimulant first when in doubt is a risky choice: while it would help an ADHD patient, it will also hurt a bipolar patient who will escalade straight into severe mania.