Table 1

Pros and cons of current digital mood tracking techniques

TechnologyProsCons
Electronic self-report
Digital EMA
  • Can easily administer questionnaires and elicit immediate responses from participants

  • Can use validated rating scales

  • Increased compliance compared with pen-and-paper surveys

  • Repeated questionnaires can become burdensome to participants

  • Frequency of EMA can be intrusive

  • Reliance on self-reported information

Behavioural monitoring
GPS
 Location and behaviour tracking
  • Basic technology embedded in normal smartphone devices (therefore easily accessible and cheap)

  • Location and movement does not immediately translate to social interaction

Phone activity
 Internet usage (including social media)
  • Data are easily recorded

  • Non-invasive

  • Longitudinal monitoring

  • Does not necessarily reflect social activity (not face-to-face interactions)

  • Connectivity issues

 Calls logs
  • Data are easily recorded

  • Non-invasive

  • Longitudinal monitoring

  • Individuals are typically very unpredictable and variable—hard to determine what may be abnormal for each individual

 Speech analysis
  • Data are easily recorded

  • Non-invasive

  • Longitudinal monitoring

  • May be subject to recall bias—voice could be modified due to recalling a previous emotional time

  • Advanced programs analysis required

Physiological monitoring
Wearables
 EEG (eg, headband or hat)
  • Unparalleled access to real-time neural activity

  • Non-compliance, not feasible to wear continuously

  • Advanced programs and analysis required

 HRV (eg, shirt or multisensor watch)
  • HRV is a empirically supported psycho-physiological biomarker— immediate HRV feedback is important for research and also for monitoring clinical care

  • Expensive to create electrodes embedded into shirts

  • Not feasible to always wear HRV monitoring shirt

  • Not very accurate recording from multisensor watches

  • Advanced programs and analysis required

 Skin conductance (eg, socks)
  • Easily assess arousal and stress levels

  • Expensive to create and monitor

  • Not feasible to wear all of the time

  • Advanced programs and analysis required

  • EMA, ecological momentary assessment; GPS, global positioning system; HRV, heart rate variability.