Answer to Question 1
Answer: Depression is accompanied by disorder of sleep in which sleep is shallow and fragmented. REM sleep comes on earlier in the night, and the first half of the night contains more REM periods. Sleep deprivation, either total deprivation or deprivation of REM sleep only, can alleviate depression. The suppression or delay of REM sleep appears to be involved in alteration of mood. Drugs that suppress REM sleep are antidepressant, and ECT both lifts mood and suppresses REM sleep.
Answer to Question 2
Answer: Positive symptoms represent additions to normal behaviors. Hallucinations are perceptions that occur in the absence of a sensory stimulus. Delusions are incorrect beliefs that are resistant to change. Negative symptoms are represented by behaviors that are missing, such as poverty of speech or flattened emotional response. Overactivity of the dopamine system is thought to play a key role in the production of positive symptoms. Antipsychotic drugs block dopamine receptors, and stimulation of dopamine results in positive symptoms. Negative symptoms are also seen after brain trauma, and it appears that degeneration/loss of brain neurons occurs in schizophrenia.