Final answer:
The client likely suffers from bipolar disorder, characterized by manic episodes without periods of depression, distinguishing it from other mental disorders like schizophrenia or OCD.(c)
Step-by-step explanation:
If a client always talks fast, possesses incredible energy, has grandiose plans, and shows hyperactive behavior without any signs of depression, they are likely suffering from bipolar disorder.
Bipolar disorder, previously known as manic depression, involves episodes of elevated mood or mania, which contrasts with major depressive disorder which involves periods of prolonged and severe low mood. While schizophrenia includes symptoms such as hallucinations and delusions, and OCD features repetitive, obsessive thoughts and compulsions, neither reflects the behaviors described. Thus, the correct answer is c) Bipolar disorder.