1. Men and women, ages of 18-65 years, inclusive.

2. Participants will have a DSM-5 bipolar disorder that is clinically stable.

3. Participants will have received a stable major psychotropic drug regimen (except for minor dosage adjustments) for at least 3 months prior study entry. Major psychotropic drugs are antipsychotics, mood stabilizers, and antidepressants. Subjects may have had changes in adjunctive benzodiazepines and hypnotic agents.

4. Participants will be obese (defined as a BMI ≥ 30 mg/kg2) or overweight (defined as BMI ≥ 27 kg/m2) with at least one weight-related comorbidity, such as hypertension, type 2 diabetes, or dyslipidemia.

5 Participants in treatment for a weight-related comorbidity (hypertension, type 2 diabetes, and/or dyslipidemia) must be on a stable and allowed treatment regimen for that condition for at least 3 months prior to study enrollment.

6 Participants will be able to provide informed consent before any trial-related activities.

1. Women who are pregnant, lactating, or of childbearing potential who are not using adequate contraceptive measures. The following are considered to be adequate methods of birth control: 1.Intrauterine device (IUD); 2. Barrier protection; 3.Contraceptive implantation system (Norplant); 4.Oral contraceptive pills; 5. A surgically sterile partner; and 6. Abstinence. Women who are > 2 years post-menopausal or surgically-sterile are not considered of childbearing potential. All female participants will have a negative pregnancy test prior to randomization.

2. Participants who have made a suicide attempt in the last 10 years, who are displaying clinically significant psychotic features, suicidality, or homicidality on mental status examination, or who have suicidal ideation or behavior as assessed with the C-SSRS.

3. Participants who are receiving behavioral weight loss treatment (BWLT) (e.g., Weight Watchers) that was begun within the 3 months before study entry. Participants who are receiving BWLT that was started 3 months prior to the beginning of the study will be allowed to continue to receive their BWLT during the trial only if they have had no weight loss in the past 3 months and they agree to not make any changes in the frequency or nature of their BWLT during the course of the drug trial.

4. A DSM-5 diagnosis of a substance-related or addictive disorder (except a tobacco-related disorder) within the 3 months prior to enrollment.

5. A DSM-5 diagnosis of dementia, a psychotic disorder, or a depressive disorder.

6. History of any psychiatric disorder which might interfere with a diagnostic assessment, treatment, or compliance.

7. Clinically unstable medical disease, including cardiovascular, hepatic, renal, gastrointestinal, pulmonary, neurological, metabolic, endocrine, or other systemic disease. Clinically stable hypertension, type 2 diabetes, or dyslipidemia are not exclusionary.

8. Have a history of a structural cardiac abnormality, valvular cardiac disease, cardiomyopathy, serious heart rhythm abnormality, coronary artery disease, congestive heart failure, stroke, or other serious cardiovascular problem.

9. Have an ECG with significant arrhythmias or conduction abnormalities, which in the opinion of the physician investigator preclude study participation.

10. Have clinically relevant abnormal laboratory results.

11. Participants requiring treatment with any drug which might interact adversely with or obscure the action of the study medication. This includes anti-obesity drugs, psychostimulants, modafinil or armodafinil, topiramate or zonisamide, and antipsychotics. Participants receiving metformin at a stable dose for ≥ 3 months can be included.

12. Participants receiving GLP-1 based therapies, sodium-glucose co-transporter 2 inhibitors (SGLT2s), thiazolidinediones, sulfonylureas, or insulin.

13. Participants with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2.

14. Participants who have received any investigational medication within three months prior to randomization.

15. Participants previously screen-failed or randomised to participate in this trial.

16. Participants who have a known or suspected allergy to liraglutide 3.0 mg sc injection, its constituents, or related products.

17. Participants with a urine drug screen positive for a drug that, in the opinion of the investigator, is being abused.

18. Participants with a past medical history of pancreatitis.

19. Participants who had received any investigational drug within 3 months prior to this trial.

20. Participants who require bariatric surgery or are anticipated to require it during the course of the trial. If such surgery becomes warranted during the study, such patients will be excluded from the primary endpoint analysis.