This trial designed to investigate the effect of switching to aripiprazole from risperidone or paliperidone on reverse prolactin level, and consequently improve sexual dysfunction in adult patients with schizophrenia spectrum disorders and bipolar spectrum disorders.

Inclusion Criteria:

1. Age: 12-55 years (male), 12-40 (female)

2. Diagnosis: Schizophrenia spectrum disorders & bipolar spectrum disorders (only Korea) by DSM-IV-TR

3. Receiving RIS or PALI with stable dose for > 1 month by their physician;

4. Prolactin level Adult: > 20 ng/ml (male), 25 ng/ml (female) Child/Adolescent: > 20 ng/ml (male, female)

5. Children and adolescents (age: 12~17 years) having more than one sexual system dysfunction measured by 5 of the 48 UKU items (galactorrhoea, gynecomastia and erectile dysfunction for male, galactorrhea, amenorrhoea/oligomenorrhoea, and dry vagina for female) or Adults (age: 18~55 years) who are considered to have sexual/reproductive dysfunction if they had either a total score of 19 or higher; a score of 5 or higher on one question; or a score of 4 or higher on 3 questions.

6. Subjects who have consented to participate by signing an informed consent form.

   -

Exclusion Criteria:

1. Medical disorder or psychiatric comorbidity or condition known to affect prolactin, sex hormone balance or bone metabolism (i.e., unstable medical disease, Cushing's disease, chronic renal failure, thyroid dysfunction, eating disorder)
2. History of hematological and/or solid malignancies
3. Physical or functional obstruction to food intake or impaired digestive/absorptive function
4. Known hypersensitivity to any study medication (risperidone, paliperidone, and aripiprazole)
5. Insulin requiring diabetes mellitus or poorly controlled diabetes mellitus (HbA1c > 9% or change of antidiabetics treatment within the 12weeks prior to screening)
6. Uncontrolled hypertension (SBP/DBP 140/90 mmHg), congestive heart failure (NYHA class III or IV), other significant cardiovascular illness (myocardial infarction, unstable angina, cardiac arrhythmia etc.)
7. Baseline QTc interval of > 450 msec
8. Hepatic and/or renal dysfunction

1) Bilirubin level ≥ 1.5 upper normal limits 2) AST/ALT ≥ 3 UNL or 3) Serum creatinine ≥ 1.5 9. Any patient hospitalized for acute exacerbation of their condition within 2 months of randomization 10. Recent (within the past 1 month) or planned treatment with prohibited medications in the protocol

-