A brain computer interface (BCI) system includes an electroencephalogram (EEG) headset and a computing device communicatively coupled to the EEG headset. The computing device includes a memory, a processor and a display device. The memory stores instructions that, when executed by the processor, cause the processor to monitor, using the EEG headset, current extrinsic network activity and current intrinsic network activity of a 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.