An antidepressant drug treatment (ADT) may be associated with adverse effects such as manic switch or chronic irritable dysphoria. These adverse effects have been highlighted in patients with bipolar disorder but never in the general population. They may lead to prescription of sedative treatment, particularly antipsychotic drugs.

To assess whether the prescription of ADT is subsequently associated with an increased probability of prescription of an antipsychotic treatment, in the general population.

A nested case-control study was carried out in a cohort of subjects initiating a new ADT registered in the national insurance database (n = 28,145). Cases were defined as subjects receiving a new antipsychotic drug treatment. Controls did not receive any antipsychotic drug until the index date. They were compared for the probability of receiving an ADT during at least two weeks in the four weeks prior to antipsychotic initiation.

2558 subjects received an new antipsychotic drug over the follow up. After adjustment for gender, age, chronic disease status, welfare benefit, specialty of the ADT prescriber, co-prescription of other psychotropic drugs, a new antipsychotic dispensing was associated with exposure to ADT during at least two weeks in the four weeks (OR 1,42 ; IC95% 1,29-1,58 ; p < 0,0001).

The dispensing of ADT increases the risk of receiving an antipsychotic treatment, which may be a proxy for manic switch, in the general population.