Psychosis noted for the first time in a person who is later diagnosed with schizophrenia is referred to as a first-episode psychosis (FEP). Positive symptoms
Positive symptoms are those symptoms that are not normally experienced, but are present in people during a psychotic episode in schizophrenia. They include delusions, hallucinations, and disorganized thoughts and speech, typically regarded as manifestations of psychosis. Hallucinations occur at some point in the lifetimes of 80% of those with schizophrenia and most commonly involve the sense of hearing (most often hearing voices) but can sometimes involve any of the other senses of taste, sight, smell, and touch. The frequency of hallucinations involving multiple senses is double the rate of those involving only one sense. They are also typically related to the content of the delusional theme. Delusions are bizarre or persecutory in nature. Distortions of self-experience such as feeling as if ones thoughts or feelings are not really ones own, to believing that thoughts are being inserted into ones mind, sometimes termed passivity phenomena, are also common. Thought disorders can include thought blocking, and disorganized speech. Positive symptoms generally respond well to medication, and become reduced over the course of the illness, perhaps related to the age-related decline in dopamine activity. Negative symptoms
Negative symptoms are deficits of normal emotional responses, or of other thought processes.
PID or Pid may refer to:

Medicine
Pelvic inflammatory disease or pelvic inflammatory disorder, an infection of the upper part of the female reproductive system
Primary immune deficiency, disorders in which part of the bodys immune system is missing or does not function properly
Prolapsed intervertebral disc, commonly called a herniated disc

Science, technology and engineering
BBC Programme Identifier, a unique identifier for a BBC television or radio programme brand, a season or series, or an individual episode
OBD-II PIDs (on-board diagnostics parameter IDs), requests for data through an OBD connector in automotive repair
Packet Identifier, a field in a MPEG transport stream packet
Passive infrared detector, a passive infrared sensor
Persistent identifier, a long-lasting reference to a document, file, web page, or other object
Phosphotyrosine-interacting domain, also known as phosphotyrosine-binding domain, a protein domain which bind to phosphotyrosine
Photoionization detector, measures volatile organic compounds and other gases
Physical Interface Device, a class of a USB device
PID controller (proportional-integral-derivative controller), a control concept used in automation
Piping and instrumentation diagram (P&ID), a diagram in the process industry which shows the piping of the process flow etc.