True about manic-depressive psychosis is:
**Manic-Depressive Psychosis**
**Core Concept**
Manic-depressive psychosis, also known as bipolar disorder, is a complex psychiatric condition characterized by recurrent episodes of mania or hypomania, often alternating with periods of major depressive disorder. This condition is influenced by a combination of genetic, neurobiological, and environmental factors.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of manic-depressive psychosis, which involves an imbalance in neurotransmitter systems, particularly dopamine and serotonin. During manic episodes, there is an excessive release of dopamine, leading to increased activity, impulsivity, and grandiosity. In contrast, during depressive episodes, there is a deficiency of serotonin, resulting in decreased motivation, interest, and pleasure. The underlying neurobiological mechanisms are complex and involve multiple brain regions, including the prefrontal cortex, amygdala, and hippocampus.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because manic-depressive psychosis is not primarily caused by a single genetic mutation, but rather by a complex interplay of genetic and environmental factors.
**Option B:** Incorrect because while lithium is a common treatment for manic-depressive psychosis, it is not a diagnostic criterion for the condition.
**Option C:** Incorrect because while mood stabilizers, such as valproate, are used to treat manic-depressive psychosis, they are not a diagnostic criterion for the condition.
**Clinical Pearl / High-Yield Fact**
Manic-depressive psychosis often presents with a characteristic "switch" between manic and depressive episodes, which can be triggered by various factors, including sleep deprivation, stress, and substance abuse.
**Correct Answer:** D