title_body: Will I be addicted to caffeine?
upvoted_answer: According to this review published in Psychopharmacology, it is very much not a myth.
  
  
    The caffeine-withdrawal syndrome has been well characterized and there
    is sufficient empirical evidence to warrant inclusion of caffeine
    withdrawal as a disorder in the DSM and revision of diagnostic
    criteria in the ICD.
  
  
  More explicitly (emphasis my own):
  
  
    Of 49 symptom categories identified, the following 10 fulfilled
    validity criteria: headache, fatigue, decreased energy/activeness,
    decreased alertness, drowsiness, decreased contentedness, depressed
    mood, difficulty concentrating, irritability, and foggy/not
    clearheaded. In addition, flu-like symptoms, nausea/vomiting, and
    muscle pain/stiffness were judged likely to represent valid symptom
    categories. In experimental studies, the incidence of headache was 50%
    and the incidence of clinically significant distress or functional
    impairment was 13%. Typically, onset of symptoms occurred 12–24 h
    after abstinence, with peak intensity at 20–51 h, and for a duration
    of 2–9 days. In general, the incidence or severity of symptoms
    increased with increases in daily dose; abstinence from doses as low
    as 100 mg/day produced symptoms. Research is reviewed indicating that
    expectancies are not a prime determinant of caffeine withdrawal and
    that avoidance of withdrawal symptoms plays a central role in habitual
    caffeine consumption.
  
  
  As for health risks, beyond the symptoms of withdrawal, caffeine has been linked to a number of conditions, such as:
  
  
  Aortic stiffness among hypertensions patients.
  Incontinence among women
  Insomnia
  Cardiac Arrest
  
  
  So to summarize: Yes, you can be addicted to caffeine. No, it is not a myth. And it seems like you need as little as 100mg a day to be addicted, that is the equivalent of 1.5 espresso shots, according to this link.. Prolonged caffeine use can be harmful, moderation is recommended.