Effects of chronic treatment with fluvoxamine and paroxetine during adolescence on serotonin-related behavior in adult male rats

Selective Serotonin Reuptake Inhibitors (SSRIs) are designed to treat adults, but are increasingly prescribed for adolescents. SSRIs might cause permanent changes in serotonin-related behavior in adolescents, since their serotonergic system is still developing. Male Wistar rats were treated with paroxetine (15 mg/kg p.o.) or fluvoxamine (30 mg/kg p.o.) throughout adolescence. After a washout period their behavior in the elevated plus-maze, prepulse inhibition test, Forced swimming test and elevated T-maze were studied. In addition, the effects of the 5-HT_1A receptor agonist 8-OH-DPAT on sexual behavior and lower lip retraction were measured. Paroxetine mildly inhibited weight gain during treatment. Both SSRIs caused a reduction in ejaculation frequency and in time spent on the open arm of the elevated plus-maze in adult rats. Fluvoxamine slightly increased avoidance latency in the elevated T-maze compared to paroxetine. No differences between the groups were found in the other tests. Apparently, chronic treatment with SSRIs during adolescence may cause mild changes in adult behavior.