Antipsychotic and atypical antipsychotics are used to treat a wide variety of psychiatric conditions such as schizophrenia, acute mania, bipolar disorder, and depression. Recently a high number of children are being treated with antipsychotics for emotional or behavioral disorders. Therapeutic drug monitoring is in demand due to the risk of toxicity, unwanted side effects, and potential pharmacokinetic interactions. Additionally, a co-administered drug can potentially inhibit or induce the metabolism of the antipsychotic drug such as antibiotics, selective serotonin reuptake inhibitors, cigarette smoking, and barbiturates. A fast screening method for a group of typical and atypical antipsychotics has been developed which incorporates the acquisition of full scan MS and data dependent product ion spectra to screen for any untargeted analytes.