The purpose of this study is to determine whether individuals with psychotic spectrum disorders ( Schizophrenia, Schizoaffective disorder,Schizophreniform Disorder, Bipolar Disorder (Type I),Bipolar Disorder (Type II),Major Depressive Disorder With Psychotic Features,Substance-Induced Psychoses,Psychosis Not-Otherwise-Specified (NOS)randomly assigned to a stepped behavioral intervention for the prevention of weight gain will experience less weight gain than individuals who receive usual care. There are several studies that have examined the effect of pharmacological and non-pharmacological behavioural approaches for weight loss in patients with psychosis, however studies examining strategies for prevention of obesity are lacking. This study is an important and novel approach to studying the problem of obesity in those with psychosis.

The rates of obesity and related co-morbidities are several-fold higher in patients with psychosis than in the general population. In addition the life expectancy 20% shorter. Several lifestyle and illness-related factors have been implicated for these high rates, including weight gain associated with treatment with novel antipsychotics. The most important cause of death in psychosis patients is coronary heart disease (CHD), of which obesity is a major risk factor. As well, diabetes and its associated complications occur at high rates in persons with psychosis, and diabetes is both related to obesity and is an independent risk factor for CVD and mortality. It therefore seems reasonable to assume that prevention of obesity may lead to a reduced risk for CVD and diabetes. If the proposed intervention proves successful in preventing weight gain and reducing risk for CVD and diabetes, the quality and length of life for persons with psychosis will be vastly improved and medical costs reduced.

Specifically, we hypothesize that : 1a) a smaller proportion of those in the intervention will gain weight (2% or more) as compared to those receiving usual care, 1b) the mean weight gain of those randomized to the intervention will be less than the mean weight gain in those randomized to usual care 2) Increases in Body Mass Index (BMI) and waist circumference (WC) will be smaller in the intervention group as compared to the controls. 3) there will be smaller increases in cholesterol, triglycerides, blood glucose and insulin levels in the intervention group than in the control group. Exploratory analyses of changes in makers for systemic inflammation, and their relationship to weight, and lipid changes, will be conducted to develop novel hypotheses regarding mediators of CVD risk in psychosis.

The study will recruit sixty persons or outpatients with DSM-lV Psychosis with a BMI of < 30 kg/m², who have been treated for less than 2 years (Early SZ) and meet the other enrollment criteria. They will be randomly assigned in the allocation ratio 1:1 to either get a stepped behavioural intervention for prevention of weight gain (n=30) or treatment as usual (routine care, n=30). This will be a pragmatic clinical trial of 16-week duration.

Inclusion Criteria:

• Age between 14 and 45 years (inclusive)
• Male or Female gender
• DSM-IV-TR diagnosis of Schizophrenia, Schizoaffective disorder,Schizophreniform Disorder, Bipolar Disorder (Type I),Bipolar Disorder (Type II), Major Depressive Disorder With Psychotic Features, Substance-Induced Psychoses, Psychosis Not-Otherwise-Specified (NOS)
• Outpatient status at the time of randomization
• Duration of antipsychotic treatment of less than 5 years
• Ability to provide informed consent
• Female patients of childbearing potential must be using a medically accepted means of contraception
• Treatment with olanzapine, clozapine, quetiapine,risperidone or paliperidone for less than 8 weeks duration at enrollment
• BMI between 18.5 and 30

Exclusion Criteria:

• Inability to give informed consent
• Currently enrolled in a weight management program
• Currently being treated with a medication to reduce weight
• Patients with unstable or active cardiovascular illnesses (myocardial infarction, congestive heart failure, etc), active or end-stage renal disease, and unstable thyroid disease, etc

Inclusion/exclusion criteria has been intentionally limited in order to maximize the generalizability of the study.