All methods of therapy may prove to be effective in treating this friend's depression, though like many other things, they all pose differentiating characteristics, methods, and overall differ in nature. Psychodynamic therapy pivots on the concept of identification and further understanding of the cause or trigger for one's psychological problems, or a professional also helps the patient pin point certain behavioral patterns. This therapy may be effective in that it may help someone with depression to understand their triggers and patterned behavior in order to later be better at identifying them and coming up with solutions to prevent or better assess the causes or patterns. One part of Psychodynamic therapy is CBT, in which patients use their knowledge and understanding of behavior and triggers to, again, better prevent or confront them in the future. Drug therapy is also a suitable approach and in fact more medical. Patients will seek a professional diagnosis before getting prescribed medications that help increase the level of serotonin in one's brain, to help boost their mood or even energy, mindset, and more. rTMS is another therapy in which magnetic pulses are perpetuated through one's brain in order to stimulate certain areas and rid of depression or other disorders. This therapy is less common and should be resorted to if other therapies can not fully assess someone's depression.
(DISCLAIMER: GRADERS ON EDGE WILL CHECK FOR CHEATING AND PLAGARISM SO DO WHAT YOU THINK IS SMART.)