Yes, primarily pharmacists who specialize in psych will focus on medications, but in the psych/neuro area (especially in psych) the medications and/or dz states can cause physicial side effects (akathisia, tardive dyskinesia, tremors, gynecomastia, etc) that the clinician (regardless of practice (MD/NP/PA/Pharm.D) must be able to assess. How much you get into physical assessment depends largely on your ability as a clinician and freedom provided w/i practice site. In a progressive VA hospital w/ prescribing privileges the door is pretty much open to do a little bit of everything. In the avg progressive VA, you can set up you scope of practice to run your own med management clinic and manage the pts as you desire w/o MD input. Typically you see Pharm.D. doing clinics for refractory pts and/or pts w/ mult therapies w/ potential for drug interactions, etc. Fiscally, in the Dept of Mental Health (DOMH) (depending on the area) the pay can be considerably less than private sector (i.e. 10-20k/yr less) and the VA can be down right hard to get into as few people ever leave employment once getting into the VA. But clinically in the DOMH a couple of pharmacists have achieved special status to rate side effects to medications for clinical trials (i.e. pseudoparkinsonism, extrapyramidal symptoms, tardive dyskinesia, etc.).
The more you get into the pathology and/or neuroscience of psychiatry you may need to lean more to a fellowship/PhD track depending on your training and how much of a clinical role you want. At the end of the day you are a pharmacist so you typically have to relate bulk of research you do back to a drug effect in some way as that is your specialty by trade. However, this isn't necessarily limiting if you can use various methods of thought like pharmacogenomics to study how brain receptors may differ from one group of people vs another (i.e. genetic polymorphisms) or metabolic issues (possible mech for atypical antipsychotics causing elevations in glucose and/or lipids via affect on various serotonin sub-receptors and/or histamine/alpha receptors). C. Lindsay DeVane a Pharm.D. researcher at MUSC (in S. Carolina) would be a good person to look at or Larry Ereshefsky, Pharm.D. (did more research on pharmacokinetics and drug interactions) who used to teach at Univ of Texas San Antonio (UTSA) but is now in CA w/ CA Clinical Trials. There is also another group pharmacists in Iowa that do a lot of genomics research in addition to clinical duties (Vicki Ellingrod, Pharm.D and Paul Perry, PhD. are the two main researchers, they offer both fellowship and residency training). UTSA also has probably the largest psych residency program in the nation as well w/ area in mental health outcomes, VA, DOMH, etc. Either way most residency programs will familiarize the resident how to conduct various psychometric tests to evaluate severity/progression of dz(MMSE (mini-mental state exam), GDS (geriatric depression scale), HAM-D (Hamilton Depression), BPRS (Brief Psychiatric Rating Scale), and so on).
Either way I'd really look into
www.cpnp.org (I think membership is still free for students). They have a listserv in which clinical dilemmas are frequently discussed. Supply/demand varies from one yr to the next, but psych residencies aren't any more competitive than any other field as the talent pool is still growing but considerably less than other specialties (i.e. ambulatory care, oncology, critical care, etc.) Most of the residencies are in either the DOMH and/or VA system.
In short, in some ways the sky is the limit as the realm of the Pharm.D. is expanding but this tends to vary based on geographic area. Things are much more progressive the further west you go so it is kind of hard to find a psych job (let alone a descent paying one) on the East Coast (as most of the jobs are within academia). So you tend to have more options if you are willing to travel and/or are already located in the Midwest/West, but just try to continue to seek out information and try to develop a realistic plan for what you would like to do upon completing such training. After putting some of those pieces together, try to find someone out there who may already be doing such work and use that person as a template (if not a direct mentor) for your own aspirations and go from there.
List of residency/fellowship sites:
http://cpnp.org/jobs/residencies.htm
I hope this answers all of your questions.