11. 9. 2015 - 14. 9. 2015
National Institute of Mental Health, Klecany, Czech Republic
Third Medical Faculty, Charles University, Prague, Czech Republic
Institute of Clinical and Experimental Medicine, Prague, Czech Republic
Institute of Forensic Medicine and Toxicology, Prague, Czech Republic
Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovak Republic
A low sexual desire is a highly prevalent condition in general population. It is marked by absent motivation to engage in coitus and little responsiveness to partner‘s sexual solicitations. Attention slips and cognitive intrusions are often reported in intimate sexual situations. No indicated pharmacotherapy is currently available and there are little data on long term safety of off-label therapies (testosterone, bupropion, yohimbine).
Cannabis, a popular drug of abuse worldwide, is known to increase sexual arousal in approximately half of the users. However, its acute sexual effects have never been, to our knowledge, experimentally tested in human volunteers. To fill this gap, we tested, whether cannabis increases activation of brain areas known to respond to intimate heterosexual interaction.
In our open, cross over study, we repeatedly measured brain activation of 21 heterosexual recreational users of cannabis (12 men, 9 women). We used still pictures of intimate heterosexual interaction, casual heterosexual interaction and fixation cross. For detection of brain activation, we used magnetic resonance device Siemens 3T. Raw data were preprocessed and analyzed using SPM software, MaRsBar and CONN toolbox and SPSS and R statistical analytical software. We also collected subjective ratings of pictures used after the investigation. Serum THC and prolactin levels were measured at several time intervals before and after the procedure.
Our results revealed that cannabis significantly increased activation of the nucleus accumbens in subjects with prior intoxication-related aphrodisiacal experiences (Aphro+), while a suppression of n.accumbens activity was observed in subjects with no such experiences (Aphro-). This change was accompanied by significant prolactin increase in Aphro- subgroup and no prolactin change in Aphro+ subgroup. Furthermore, serum THC content significantly modulated connectivity of the hypothalamus with anterior cingulate and fronto-polar area, in women and men, respectively. Reported brain activation changes did not occur for control social stimuli. Brain changes were not reflected in subjective self-report data. Aphro- subjects (high prolactin responders) showed significantly higher scores on MMPI 2 scales depression, schizophrenia and psychasthenia.
In conclusion, our data support the idea that cannabis might bias brain processing towards the development of sexual motivational state in subjects with low provoked prolactin response, as shown by activation of nucleus accumbens, a primary reward area. Furthermore, the dosage of cannabis seems to modulate hypothalamic crosstalk with frontal areas known to relegate attention resources. Taken together, cannabis could become a promising new agent for modulation of sexual motivation in low desire subjects, through reward and attention channels. A possibility of sexual effects prediction based on prolactin response to cannabis provocation should be further investigated.
Grant support: RVO PCP/NUDZ, VG20122015080, VG20122015075, 266705/SVV/2013, P304/12/G069, PRVOUKP34, ČNPS Travel grant, VEGA 2/0057/15, GAUK 232415