Efficacy of Quetiapine in the Treatment of Patients With Schizophrenia and a Comorbid Substance Use Disorder
Condition: Schizophrenia; Schizoaffective Disorder; Psychotic Disorder; Substance Abuse; Alcohol Abuse
MeSH terms: Substance-Related Disorders; Alcoholism; Schizophrenia; Psychotic Disorders
Study type: Interventional
Phase: Phase 4

Summary: 
      The purpose of this study is to examine the efficacy of quetiapine (Seroquel) in reducing
      substance use in persons diagnosed with schizophrenia. The primary hypothesis is that
      quetiapine treatment will be associated with a decrease in substance use.
    

Detailed description: 
      Comorbid alcohol/substance use disorder (SUD) in schizophrenia is a major concern, both in
      view of the high frequency of SUD among patients with schizophrenia and the difficulty in
      managing such patients. Though antipsychotic medications are effective in reducing symptoms
      and impairment in persons with schizophrenia, the typical antipsychotic agents are of limited
      value in controlling alcohol/substance use in these patients. Extrapyramidal, dysphoric side
      effects of conventional neuroleptics may actually promote the use of substances in an attempt
      to counteract these effects.

      Novel antipsychotics have radically altered treatment expectations and outcomes for patients
      with severe forms of schizophrenia. With the greater availability of novel agents in clinical
      practice, it has been noted that these benefits have also extended to specific subgroups of
      patients including patients with comorbid SUD. Several retrospective studies have
      demonstrated a decrease in comorbid substance use in patients with schizophrenia treated with
      clozapine. There is little data available, however, on the efficacy of quetiapine in patients
      with schizophrenia and comorbid SUD. Its receptor profile, including a weak Dopamine2 (D2)
      receptor blocking ability and substantial effects at noradrenergic receptors, makes it a
      logical antipsychotic to use in the comorbid population.

      The study is an open-label investigation of the efficacy of quetiapine in a group of 30
      patients with schizophrenia and comorbid substance use disorder. Patients diagnosed with
      schizophrenia or schizoaffective disorder and a comorbid substance use disorder are switched
      to quetiapine for 12 weeks. We hypothesize that quetiapine treatment will be associated with
      a decrease in substance use. Moreover, we further hypothesize that measures of symptoms,
      cognition and quality of life will also improve over baseline assessments in patients treated
      with quetiapine. Data suggesting a beneficial effect of quetiapine will have to be confirmed
      in a prospective double-blind study. This pilot investigation will provide preliminary data
      and effect sizes that will be used in the design of this subsequent investigation.
    

Intervention name(s): Quetiapine
Intervention type(s): Drug
Intervention description(s): After patients provided informed consent and completed baseline measures, quetiapine was initiated in all participants and titrated up to a target dose of 600 mg (in divided daily doses) over two weeks as the previous antipsychotic medication was slowly tapered and discontinued. Participants met with study physicians weekly to assess tolerability and response to the medication. Concomitant medications were held constant. After the initial titration period, quetiapine was dosed in a flexible manner up to 800 mg /day, with dose adjustments based on symptomatic response and side effects.
Other intervention name(s): Seroquel
Intervention MeSH terms: Quetiapine Fumarate
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Quetiapine; Seroquel; Schizophrenia; Dual Diagnosis; Substance Abuse; Alcohol Abuse