psychiatry 

1. definition of major depression: if 5 out of 9 symptoms persist for more than 2 weeks

symptoms can be remembered with mnemonics: low mood SIGECAPS

S-sleep

I-loss of interest

G-guilty/ worthlessness

E-lack of energy

C- concentration/ attention

A-Appetite loss

P-psychomotor changes

S-suicidality

Low mood

In adjustment disorder, the precipitant can be anything except bereavement.

what is the difference between normal grief vs major depression?

In normal grief about the death of a loved one, the idea ruminates around that loved one only. she may think she would have died with her loved ones. She can feel auditory/visual hallucinations of her loved ones. But these do not significantly impair daily life functioning. these episodes occur intermittently but in major depression, these symptoms are persistent. In major depression, there is greater social and occupational dysfunction.

2. How to differentiate schizoaffective disorder from mood disorder with psychotic features and from schizophrenia?

in schizoaffective disorder, there are psychotic symptoms even in the absence of mood symptoms (there is a gap of more than 2 weeks). In other words, he may just be having hallucinations/delusions only for more than 2 weeks without mood symptoms (depression or mania).  But in depression with psychosis, both must be concurrently present.

in schizophrenia, mood symptoms are almost lacking

3. what is the difference between acute stress disorder and PTSD?

In both, there is dissociative, intrusive, and avoidance behavior but the time duration is different. if the time duration is from 3 days to 1 month, it falls under acute stress disorder and if the time duration crosses 1 month, the symptom complex falls under PTSD

4. What is adjustment disorder?

if the symptom complex does not meet another diagnosis, after that you can consider adjustment disorder.

5. what is cyclothymia?

Hypomania and depression alternating for 2 years

6. what are the symptoms of methylphenidate abuse?

Hypertension, tachycardia, psychosis (aggressiveness, irritability)