Does personality play a relevant role in the placebo effect?

Department of Psychiatry, University Hospital Center Zagreb, Kišpatićeva 12, 10 000 Zagreb, Croatia, .
Psychiatria Danubina (Impact Factor: 0.65). 03/2013; 25(1):17-23.
Source: PubMed

ABSTRACT Subjective factors influencing placebo response have been a focus of numerous theoretical conceptualizations and empirical research. One such factor, individual's personality, has been linked to different clinical conditions, their expressions and treatment outcomes. Thus, there is little surprise many researchers have tried to identify placebo-prone personality over the years. Because of certain methodological and conceptual issues of the earlier studies, these efforts have not been very fruitful. However, recent scientific endeavours, facilitated by improved experimental designs and neuroimaging technology, have 'reignited the old fires'. It is now suggested that studies exploring the placebo-related personality traits, such as optimism/pessimism, neuroticism, and novelty seeking, need to take into account situational variables (e.g., positive or negative expectations, patient-clinician relationship) and relevant underlying neurobiological mechanisms (e.g., endogenous opioid and dopaminergic systems). Even though many questions still remain to be answered, such as the identification of different situational variables interacting with personality traits, exploration and better understanding of placebo-related personality would facilitate the use of placebo in clinical practice and improve the methodology of clinical trials.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The study explored the association between temperament and character and medication adherence in 76 patients with schizophrenia. Patients were assessed with the Temperament and Character Inventory, the Beck Depression Inventory, and the Positive and Negative Syndrome Scale. First-degree relatives were used as informants on adherence. The patients differed in their adherence based on the effect of gender, as males were found to be less adherent than females. Adherence differed based on novelty seeking. The temperament of the patient should be considered during the assessment of adherence.
    Psychiatry Research 03/2011; 186(1):141-3. · 2.68 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Reward processing depends on dopaminergic neurotransmission and is modulated by factors affecting dopamine (DA) reuptake and degradation. We used fMRI and a guessing task sensitive to reward-related activation in the prefrontal cortex and ventral striatum to study how individual variation in genes contributing to DA reuptake [DA transporter (DAT)] and degradation [catechol-o-methyltransferase (COMT)] influences reward processing. Prefrontal activity, evoked by anticipation of reward irrespective of reward probability and magnitude, was COMT genotype-dependent. Volunteers homozygous for the Met allele, associated with lower enzyme activity and presumably greater DA availability, showed larger responses compared with volunteers homozygous for the Val allele. A similar COMT effect was observed in the ventral striatum. As reported previously, the ventral striatum was also found to code gain-related expected value, i.e., the product of reward magnitude and gain probability. Individual differences in ventral striatal sensitivity for value were in part explained by an epistatic gene-gene interaction between COMT and DAT. Although most genotype combinations exhibited the expected activity increase with more likely and larger rewards, two genotype combinations (COMT Met/Met DAT 10R and COMT Val/Val 9R) were associated with blunted ventral striatal responses. In view of a consistent relationship between reduced reward sensitivity and addiction, our findings point to a potential genetic basis for vulnerability to addiction.
    Proceedings of the National Academy of Sciences 06/2007; 104(19):8125-30. · 9.81 Impact Factor
  • Advances in Psychiatric Treatment 07/2006; 12(4):287-296.


Available from
May 22, 2014