Recreational Use of Erectile Dysfunction Medication May Decrease Confidence in Ability to Gain and Hold Erections in Young Males

P. Santtila; N. K. Sandnabba; P. Jern; M. Varjonen; K. Witting; B. von der Pahlen


Int J Impot Res. 2007;19(6):591-596. 

In This Article


The analyses presented in the present study were based on 4428 male twins and their siblings who had provided information on their use of erection medication. The mean age of the males was 29.51 (s.d. = 6.77) years. The participants consisted of 3492 twins and 936 of their male siblings. Of the participants, 70.9% had a regular sexual partner and 8.5% reported having engaged in sexual behavior with a member of the same sex at some point in their lives.

Participants were a subset from the Genetics of Sex and Aggression (GSA) Sample. The main GSA sample consists of two different data collections. The first data collection was carried out in 2005 and targeted 33- to 43-year-old twins. Twin pairs were sampled beginning from 33-year-old twins and progressing toward older twins until a final sample of 5000 twin pairs (10,000 individuals) had been identified. Questionnaires followed by a reminder letter and later a new questionnaire were sent to these individuals and finally returned by 3604 both male and female respondents resulting in an overall response rate of 36%. The response rate was lower for male (27%) when compared to female (45%) respondents.

The second data collection was carried out in 2006 and targeted 18- to 33-year-old (there was no overlap between the data collections) twins and their over 18-year-old siblings. A total of 23,577 individuals were contacted by postal mail and asked if they would be interested in completing a questionnaire and to give saliva samples for DNA and hormone analyses (as the present study does not report on the DNA and hormone samples, no further information is given regarding them). Participants who consented to participate were given the option of completing the questionnaire by postal mail or online, through a secure webpage. Those who did not want to receive the questionnaire were instructed to notify the researchers of that by either returning the inquiry of interest in a pre-paid envelope or through the webpage. Next, the questionnaire was sent followed by a reminder letter. A separate simultaneous longitudinal twin study was being conducted including some of the targeted individuals. Therefore, the reminder letters were only sent to individuals unique for the present study. Finally, a total of 10,524 both male and female participants responded to the survey, yielding an overall response rate of 45%. The response rate was lower for male (34%) than for female (56%) respondents. It should be noted that the response rates for both data collections represent underestimates due to changing addresses. According to Statistics Finland ( approximately 15% of Finns move each year. Considering that the data collections lasted in each instance for over half a year, the real response rate was approximately 40% for the first and 50% for the second data collection. In all, a total of 4645 males returned the questionnaire. There were no differences between those providing information on their EDM use and those not doing so in terms of ED or confidence in erection.

For both data collections, the participants' addresses were obtained from the Finnish population registry. In the materials sent to the participants, the purpose of the study was described closely and the voluntary and anonymous nature of the participation was explained. The research plan for the first data collection consisting only of a questionnaire study was approved by the Ethics Committee of the Department of Psychology at Åbo Akademi University and for the second data collection also including DNA and hormone samples by the newly set up Ethics Committee of the Åbo Akademi University.

Erectile Dysfunction Medication Use. The participants first indicated if they have used an oral EDM (such as Viagra or Cialis) during the previous 4 weeks. If they responded yes, they were asked to explain whether it was to treat an ED diagnosed by a physician or for recreational reasons. The participants were also asked to indicate in how many of their intercourses during the previous 4 weeks they had been using erection medication. The response options were had not had sex, had used EDM never or almost never, a few times (less than 50%), sometimes (approximately 50%), most times (over 50%) and always or almost always. The responses were changed into a numerical scale with the value of 0 given to the 'had not had sex option', and the value of 5 to the 'always or almost always option'. These items were created specifically for the current study.

Erectile Dysfunction During First Intercourse Experience. The participants indicated whether the following items were true concerning their first intercourse experience: passing erection problems, erection problems that precluded penetration, erection problems that precluded ejaculation and fear of losing erection. The response options were true and not true. This measure was created specifically for the current study.

Current Erectile Function. To investigate problems with erectile function, the brief version of the IIEF was used.[13] The IIEF is an originally a 15-item self-report questionnaire designed to measure five aspects of male sexual behavior and function: erectile function, intercourse satisfaction, orgasmic function, sexual desire and overall satisfaction. Overall, the IIEF has been shown to have excellent reliability (Cronbach's α = 0.91) with the items measuring erectile function having alphas between 0.91 and 0.96. Test-retest reliability was also high (r = 0.82).[13] In its abbreviated form, the IIEF-5, five items designed to measure only erectile function have been chosen; erection confidence, erection firmness, erection maintenance, erection maintenance frequency and intercourse satisfaction. The IIEF-5 has been shown to be an equally reliable diagnostic tool.[14]

Unrestricted Sexual Behavior. Three items from the Sociosexual Orientation Inventory (SOI),[17] were used to assess differences in the sexual behavior of the participants. Since its introduction, the SOI has acquired great international acknowledgement and it has been widely used in various studies of basic human mating strategies.[18] The three items were: Number of partners in past year: 'With how many different partners have you had sexual intercourse within the past year?', Number of partners foreseen: 'With how many different partners do you realistically foresee having sexual intercourse during the next five years?' and Number of one-night stands: 'With how many different partners have you had sexual intercourse on one and only one occasion?'. There were 89 responses exceeding the value of 50 on these open-ended items and these were recoded into the value of 50 to avoid a distributional skew due to extreme scores. In addition, we used an item assessing the age (in years) at which the participants had experienced their first intercourse to explore differences in unrestricted sexual behavior.

More Than One Ejaculation During a Single Sexual Encounter. The participants indicated in what proportion of their sexual interactions they had received more than one ejaculation. The response options were never or almost never, a few times (less than 50%), sometimes (approximately 50%), most times (over 50%) and always or almost always. The responses were changed into a numerical scale with the value of 1 given to the never or almost never option, and the value of 5 to the always or almost always option. This item was created specifically for the current study.

Confidence in Ability to Gain and Hold Erections. The participants indicated the level of their trust in their ability of gaining and holding erections during the past 4 weeks. The response options were very low, low, moderate, high and very high. These responses were changed into a numerical scale with the value of 1 given to the very low and the value of 5 to the very high option. This item was taken from the (IIEF).[13]

Both the group comparisons and association analyses were conducted with the General Linear Model of the SPSS for Windows (version 14) Complex Samples module. This module takes into account the dependence between the members of the same families that was a feature of our sample as it included several siblings from the same families. If such dependence is not taken into account, the variance within a group is underestimated. The R 2 effect size estimates from these analyses were reported to indicate the proportion of variance explained by the independent variables. For association analyses, both Pearson correlations (r p) as well as regression coefficients (B) with associated standard errors (s.e.) were reported. In all analyses, age was used as a covariate. No other covariates were included.


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