Effects of paroxetine on emotional functioning and treatment awareness: a 4-week randomized placebo-controlled study in healthy clinicians

[What can we expect from clinical trials in psychiatry?]

Clinical trials in psychiatry allow to build the regulatory dossiers for market authorization but also to document the mechanism of action of new drugs, to build pharmacodynamics models, evaluate the treatment effects, propose prognosis, efficacy or tolerability biomarkers and altogether to assess the impact of drugs for patient, caregiver and society. However, clinical trials have shown some limitations. Number of recent dossiers failed to convince the regulators. The clinical and biological heterogeneity of psychiatric disorders, the pharmacokinetic and pharmacodynamics properties of the compounds, the lack of translatable biomarkers possibly explain these difficulties. Several breakthrough options are now available: quantitative system pharmacology analysis of drug effects variability, pharmacometry and pharmacoepidemiology, Big Data analysis, brain modelling. In addition to more classical approaches, these opportunities lead to a paradigm change for clinical trials in psychiatry.

Mood and personality effects in healthy participants after chronic administration of sertraline

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) are utilised in the treatment of a wide range of disorders but the neuropsychological basis of their therapeutic efficacy remains unclear. In this study we examine the impact of 3 weeks administration of sertraline, an SSRI, on mood and personality in a group of healthy volunteers to understand the effect of these agents in the absence of clinical disorder.

METHODS

Thirty-eight healthy women and men, with no personal or familial history of Axis I disorder were randomised to receive either a placebo or sertraline (50mg/day p.o.) for an average of 23 days, in a double-blind design. Self-report indices of mood and personality, and genotype (5-HTTLPR) and sertraline bioavailability were assessed.

RESULTS

Chronic administration of an SSRI was found to alter mood and personality. The SSRI group experienced a significant decrease in negative affect (NA), guilt and attentiveness, and significant increases in positive affect (PA), joviality, self-assurance and serenity. Genotype and bioavailability of sertraline did not moderate these findings, however gender did. Only females demonstrated increased PA and joviality, and decreased NA; whereas, only males demonstrated decreased attentiveness.

LIMITATIONS

Greater power and a more specific manipulation of serotonergic functioning would help clarify the neurochemical basis of these findings.

CONCLUSIONS

Results from the current study demonstrate that longer term administration of SSRIs alters aspects of mood and personality in the absence of disorder. This suggests that these agents have effects on basic psychological processes that may in turn form the basis of their therapeutic efficacy.

Antidepressants in healthy subjects: what are the psychotropic/psychological effects?

A wide debate is ongoing regarding whether antidepressant effects should be considered a general property of these agents or whether they exclusively belong to the context of target symptoms. The aim of the present review is to summarize findings on antidepressant influences on healthy volunteers, focusing on changes in psychological and cognitive functions. Differences have been detected between acute and chronic treatments. Acute treatment has been found to lead to positive bias in emotion processing and facilitation in negative emotion recognition. Chronic treatments have been found to stabilise some changes induced by acute treatment, such as increased social behaviours. Regarding antidepressant modulation of affective symptomatology contrasting results have been reported suggesting that the link between action on cognitive processes and mood may be not direct. In fact, meta-analyzing data on mood and anxiety symptoms no difference was detected between subjects receiving placebo and SSRIs. However, meta-analyzing data on negative affects, a significant decrease was detected in subjects receiving SSRIs in comparison with subjects receiving placebo. In summary, antidepressants seem to exert a detectable influence also in healthy subjects.