Depression/anxiety may be a side effect of Parkinson's medication

How is mood affected in people with Parkinson’s? BlackRod Feb '12
An area that I think needs to be addressed is the depression/anxiety that may be a side effect of Parkinson’s medication.

Dewey Feb '12
The non-motor symptoms arising from Parkinson’s and as side effects of the medication end up being more trouble for most people than the motor symptoms for which they are being treated.

Risks and side effects of levodopa drugs [include] …anxiety and depression, hallucinations… sleep problems
SINEMET Generic Name: carbidopa-levodopa Last reviewed on RxList: 3/16/2020
SIDE EFFECTS [include]: Nervous System/Psychiatric

Psychotic episodes including delusions, hallucinations, and paranoid ideation,
bradykinetic episodes (“on-off” phenomenon),
confusion, agitation, dizziness,
somnolence, dream abnormalities including nightmares, insomnia,
paresthesia, headache,
depression with or without development of suicidal tendencies,
pathological gambling, increased libido including hypersexuality, impulse control symptoms.
Madopar 50 mg/12.5 mg Dispersible Tablets Roche Products Limited Last updated on emc: 08 Apr 2020
Active ingredient: levodopa, benserazide hydrochloride
This information is intended for use by health professionals

4.4 Special warnings and precautions for use
Depression can be part of the clinical picture in patients with Parkinson’s disease and may also occur in patients treated with Madopar. All patients should be carefully monitored for psychological changes and depression with or without suicidal ideation.

4.8 Undesirable effects [includes] Psychiatric Disorders
Confusional state, Depression, Agitation, Anxiety, Hallucination, Insomnia, Disorientation

Psychiatric aspects of Parkinson’s disease S.Grover, M.Somaiya, S.Kumar, and A.Avasthi J Neurosci Rural Pract. 2015 Jan-Mar; 6(1): 65–76.

When compared to drug naïve patients those on antiparkinsonian medications have higher rates of depression (75.5% versus 59.2%).

With regards to treatment of depression in patients with PD, few randomized controlled trials (RCTs) have evaluated the efficacy of various antidepressant medications.

Another recent meta-analysis that included 11 RCTs calculated the odds ratio for the efficacy of various agents… On the basis of these findings, the authors concluded that the evidence does not support the use of SSRIs, pramiprexole, pergolide and SNRIs as antidepressants in patients with PD.

At the first step, whenever a patient with PD presents with depression there is a need to assess the relationship of depression with medications used for the management of PD and if required dose of anti-parkinsonian medications should be adjusted.

From the psychiatrist point of view, it is important to understand that various psychiatric manifestations in patients with PD may be due to the same neuro-degenerative process that is responsible for the motor symptoms; additionally the psychiatric symptoms may be associated with the medications used for management of motoric symptoms of PD.