Depression brain computer interface for the quantitative assessment of mood state and for biofeedback for mood alteration

A mobile communications device comprising:

• a headset removably attached to the mobile communications device, the headset comprising:
• at least one speaker to output audio from the mobile communications device;
• a band configured to be positioned adjacent a head of a patient;
• a plurality of EEG electrodes coupled to the band;
• a processor,
• a display device, and
• a memory, the memory storing instructions that, when executed by the processor, cause the processor to:
• monitor, using the plurality of EEG electrodes, current extrinsic network activity and current intrinsic network activity of the patient;
• generate a current depression index based on the relationship between the current extrinsic network activity and the current intrinsic network activity;
• and
• display, on the display device, a representation of the relationship between the current depression index and a baseline depression index previously generated for the patient.