This document summarizes various methods that have been used to predict depression. It discusses using questionnaires and psychometric tests administered by psychiatrists, analyzing EEG signals through signal processing techniques, and using artificial intelligence and machine learning algorithms to analyze text, audio, and visual inputs. Specifically, it describes using standardized tests like the Hospital Anxiety and Depression Scale and Beck's Depression Inventory, extracting features from EEG frequency bands to classify subjects, and employing sentiment analysis and other text analysis on speech, facial expressions, and head movements to predict mental states. The document provides background on relevant concepts in artificial intelligence, machine learning, deep learning, and neural networks.