are paroxetine and quetiapine similar?

Not really but they may be used to treat similar sort of conditions.

Paroxetine is an antidepressant in a group of drugs called selective serotonin reuptake inhibitors (SSRIs). It works by restoring the balance of serotonin, a natural substance in the brain, which helps to improve certain mood problems

Paroxetine is used to treat depression, obsessive-compulsive disorder, anxiety disorders, post-traumatic stress disorder (PTSD), and premenstrual dysphoric disorder (PMDD).

http://www.drugs.com/paroxetine.html

And Quetiapine is an antipsychotic medication. It works by changing the actions of chemicals in the brain.

Quetiapine is used to treat the symptoms of psychotic conditions such as schizophrenia and bipolar disorder (manic depression).

http://www.drugs.com/mtm/quetiapine.html