Using marijuana affects your brain in a complex process and changes the functions of your body and brain over a period of time. This also shows why marijuana is used in medical purposes and associated as a treatment for different illnesses like Alzheimer's, depression, anxiety, cancer, sleeping disorders, etc.
Actual patients who started using medical marijuana for the treatment of their mental health disorder have experienced relief from the different symptoms. Clinical studies have already proven that low doses of marijuana use results in an increased level of  serotonin, an important factor in mood elevation. Patients suffering with PTSD or anxiety have reported a feeling of relaxation. When depression is linked to some of the chronic medical conditions like chronic pain or cancer, patients see an improvement in mood that is being sustained. Perhaps, the most essential benefit of marijuana as an alternative to traditional medications is lack of harmful and fatal side effects, and its safety.
Today, many psychiatrists and mental health professionals are already recognizing the numerous benefits that medical marijuana can provide for different mental conditions like Alzheimer's, anxiety, PTSD, depression and several others. Many patients undergoing medical marijuana treatment showed an improvement in their moods and a decrease in the symptom occurrence, with fewer side effects. The use of marijuana acording to marillow.com can be helpful if you properly use it and with the advice of a medical professional.

here is some side effects,

Lithium:

• worsened the RLS sypmtoms considerably. I was prescribed an anticonvulsant which caused insomnia, sleeping pills against the insomnia then amphetamines so I could get out of bed in the morning

Prozac:

• I became highly aggressive.
• I had nightmares of being the shooter in mass shootings in grade schools and preschools
• hightened alcohol use, likely to cope with the above
• became emotionally “empty” like I was incapable of feeling anything

Paxil:

• see prozac, different drug same effect

Zoloft:

• emotional emptyness
• Highly aggressive
• I had fantasies of snapping complete strangers necks just to hear the sound of it snapping
• nightmares
• sleeping problems, likely related to the nightmares
• worsened RLS symptoms

Cannabis:

• increased appatite
• my weight stays relatively stable at 150 Pounds
• I grin a bit more often
• I sleep very well and deep. Trust me on this. Stones don’t sleep as deep as I do
• I drink one hell of a lot less alcohol
• I can enjoy spending time with my family without feeling guilty about it later
• Occasional dry mouth

You can decide whats worse, but I’d rather eat, drink and grin then have nightmares about murdering young children